Linus Pauling

Linus Pauling

Overview

Linus Carl Pauling was an American chemist
Chemist
A chemist is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties such as density and acidity. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms...

, biochemist
Biochemist
Biochemists are scientists who are trained in biochemistry. Typical biochemists study chemical processes and chemical transformations in living organisms. The prefix of "bio" in "biochemist" can be understood as a fusion of "biological chemist."-Role:...

, peace activist
Peace activist
This list of peace activists includes people who proactively advocate diplomatic, non-military resolution of political disputes, usually through nonviolent means.A peace activist is an activist of the peace movement.*Jane Addams*Martti Ahtisaari...

, author
Author
An author is broadly defined as "the person who originates or gives existence to anything" and that authorship determines responsibility for what is created. Narrowly defined, an author is the originator of any written work.-Legal significance:...

, and educator. He was one of the most influential chemists in history and ranks among the most important scientists of the 20th century. Pauling was among the first scientists to work in the fields of quantum chemistry
Quantum chemistry
Quantum chemistry is a branch of chemistry whose primary focus is the application of quantum mechanics in physical models and experiments of chemical systems...

 and molecular biology
Molecular biology
Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...

.

Pauling is one of only four individuals to have won more than one Nobel Prize
Nobel Prize
The Nobel Prizes are annual international awards bestowed by Scandinavian committees in recognition of cultural and scientific advances. The will of the Swedish chemist Alfred Nobel, the inventor of dynamite, established the prizes in 1895...

. He is one of only two people awarded Nobel Prizes in different fields (the chemistry and peace prizes), the other being Marie Curie
Marie Curie
Marie Skłodowska-Curie was a physicist and chemist famous for her pioneering research on radioactivity. She was the first person honored with two Nobel Prizes—in physics and chemistry...

 (the Chemistry and Physics prizes), and the only person awarded two unshared prizes.

Pauling was born in Portland, Oregon
Portland, Oregon
Portland is a city located in the Pacific Northwest, near the confluence of the Willamette and Columbia rivers in the U.S. state of Oregon. As of the 2010 Census, it had a population of 583,776, making it the 29th most populous city in the United States...

, as the first-born child of Herman Henry William Pauling (1876-1910) and Lucy Isabelle "Belle" Darling (1881-1926).
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Unanswered Questions
Quotations

The only sane policy for the world is that of abolishing war.

Nobel Lecture for The Nobel Peace Prize 1962 (11 December 1963)

I have always wanted to know as much as possible about the world.

Linus Pauling In His Own Words (1995) by Barbara Marinacci ISBN 0684813874

Only when I began studying chemical engineering at Oregon Agricultural College did I realize that I myself might discover something new about the nature of the world.

Linus Pauling In His Own Words (1995) by Barbara Marinacci

What astonished me was the very low toxicity of a substance that has such very great physiological power. A little pinch, 5 mg, every day, is enough to keep a person from dying of pellagra, but it is so lacking in toxicity that ten thousand times as much can [sometimes] be taken without harm. (word in brackets added)

About vitamin B3, (either niacin or niacinamide), in How to Live Longer and Feel Better,, 1986, Avon Books, ISBN 0-380-70289-4 , page 24.

"I have something that I call my Golden Rule. It goes something like this: 'Do unto others twenty-five percent better than you expect them to do unto you.' [Pause.] The twenty-five percent is for error."

Pauling's reply to an audience question about his ethical system, following his lecture circa 1961 at Monterey Peninsula College, in Monterey, California.
Encyclopedia

Linus Carl Pauling was an American chemist
Chemist
A chemist is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties such as density and acidity. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms...

, biochemist
Biochemist
Biochemists are scientists who are trained in biochemistry. Typical biochemists study chemical processes and chemical transformations in living organisms. The prefix of "bio" in "biochemist" can be understood as a fusion of "biological chemist."-Role:...

, peace activist
Peace activist
This list of peace activists includes people who proactively advocate diplomatic, non-military resolution of political disputes, usually through nonviolent means.A peace activist is an activist of the peace movement.*Jane Addams*Martti Ahtisaari...

, author
Author
An author is broadly defined as "the person who originates or gives existence to anything" and that authorship determines responsibility for what is created. Narrowly defined, an author is the originator of any written work.-Legal significance:...

, and educator. He was one of the most influential chemists in history and ranks among the most important scientists of the 20th century. Pauling was among the first scientists to work in the fields of quantum chemistry
Quantum chemistry
Quantum chemistry is a branch of chemistry whose primary focus is the application of quantum mechanics in physical models and experiments of chemical systems...

 and molecular biology
Molecular biology
Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...

.

Pauling is one of only four individuals to have won more than one Nobel Prize
Nobel Prize
The Nobel Prizes are annual international awards bestowed by Scandinavian committees in recognition of cultural and scientific advances. The will of the Swedish chemist Alfred Nobel, the inventor of dynamite, established the prizes in 1895...

. He is one of only two people awarded Nobel Prizes in different fields (the chemistry and peace prizes), the other being Marie Curie
Marie Curie
Marie Skłodowska-Curie was a physicist and chemist famous for her pioneering research on radioactivity. She was the first person honored with two Nobel Prizes—in physics and chemistry...

 (the Chemistry and Physics prizes), and the only person awarded two unshared prizes.

Early years


Pauling was born in Portland, Oregon
Portland, Oregon
Portland is a city located in the Pacific Northwest, near the confluence of the Willamette and Columbia rivers in the U.S. state of Oregon. As of the 2010 Census, it had a population of 583,776, making it the 29th most populous city in the United States...

, as the first-born child of Herman Henry William Pauling (1876-1910) and Lucy Isabelle "Belle" Darling (1881-1926). He was named "Linus Carl," in honor of Lucy's father, Linus, and Herman's father, Carl. Herman and Lucy-then 23 and 18 years old, respectively-had met at a dinner party in Condon
Condon, Oregon
Condon is a city in Gilliam County, Oregon, United States. The population was 759 at the 2000 census. It is the county seat of Gilliam County. It is located on Oregon Route 19....

. Six months later, the two were married.

Herman Pauling was descended from South-German farmers, who had immigrated to a German
Germans
The Germans are a Germanic ethnic group native to Central Europe. The English term Germans has referred to the German-speaking population of the Holy Roman Empire since the Late Middle Ages....

 settlement in Concordia
Concordia, Missouri
Concordia is a city in Lafayette County, Missouri, United States. The population was 2,360 at the 2000 census.-Geography:Concordia is located at . According to the United States Census Bureau, the city has a total area of , all of it land.-Demographics:As of the census of 2000, there were 2,360...

, Missouri
Missouri
Missouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...

. Carl Pauling moved his family to California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

, before settling in Oswego. There he worked as an ironmonger at a foundry
Foundry
A foundry is a factory that produces metal castings. Metals are cast into shapes by melting them into a liquid, pouring the metal in a mold, and removing the mold material or casting after the metal has solidified as it cools. The most common metals processed are aluminum and cast iron...

. After completing grammar school, Herman Pauling served as an apprentice to a druggist. Upon completion of his services, he became a wholesale bread salesman.

Pauling's mother, Lucy, of English/Scottish descent, was the daughter of Linus Wilson Darling, who had served as a teacher
Teacher
A teacher or schoolteacher is a person who provides education for pupils and students . The role of teacher is often formal and ongoing, carried out at a school or other place of formal education. In many countries, a person who wishes to become a teacher must first obtain specified professional...

, farmer
Farmer
A farmer is a person engaged in agriculture, who raises living organisms for food or raw materials, generally including livestock husbandry and growing crops, such as produce and grain...

, surveyor
Surveying
See Also: Public Land Survey SystemSurveying or land surveying is the technique, profession, and science of accurately determining the terrestrial or three-dimensional position of points and the distances and angles between them...

, postmaster
Postmaster
A postmaster is the head of an individual post office. Postmistress is not used anymore in the United States, as the "master" component of the word refers to a person of authority and has no gender quality...

 and lawyer
Lawyer
A lawyer, according to Black's Law Dictionary, is "a person learned in the law; as an attorney, counsel or solicitor; a person who is practicing law." Law is the system of rules of conduct established by the sovereign government of a society to correct wrongs, maintain the stability of political...

 at different points of his life. Linus Darling was orphaned at the age of 11 and apprenticed under a baker
Baker
A baker is someone who bakes and sells bread, Cakes and similar foods may also be produced, as the traditional boundaries between what is produced by a baker as opposed to a pastry chef have blurred in recent decades...

 before becoming a schoolteacher. He fell in love with a young woman named Alice from Turner
Turner, Oregon
Turner is a city in Marion County, Oregon, United States. The population was 1,199 at the 2000 census. It is part of the Salem Metropolitan Statistical Area...

, Oregon
Oregon
Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...

, whom he eventually married. On July 17, 1888, Alice gave birth to the couple's fifth child, but he was stillborn
Stillbirth
A stillbirth occurs when a fetus has died in the uterus. The Australian definition specifies that fetal death is termed a stillbirth after 20 weeks gestation or the fetus weighs more than . Once the fetus has died the mother still has contractions and remains undelivered. The term is often used in...

. Less than a month later, she died, leaving Darling to take care of their four young daughters.

Linus Pauling spent his first year living in a one-room apartment with his parents in Portland
Portland, Oregon
Portland is a city located in the Pacific Northwest, near the confluence of the Willamette and Columbia rivers in the U.S. state of Oregon. As of the 2010 Census, it had a population of 583,776, making it the 29th most populous city in the United States...

. In 1902, after his sister Pauline was born, Pauling's parents decided to move out of the city. They were crowded in their apartment, but couldn't afford more spacious living quarters in Portland. Lucy stayed with her husband's parents in Oswego, while Herman searched for new housing. Herman brought the family to Salem
Salem, Oregon
Salem is the capital of the U.S. state of Oregon, and the county seat of Marion County. It is located in the center of the Willamette Valley alongside the Willamette River, which runs north through the city. The river forms the boundary between Marion and Polk counties, and the city neighborhood...

, where he took up a job as a traveling salesman for the Skidmore Drug Company. Within a year of Lucile's birth in 1904, Herman Pauling moved his family to Oswego, where he opened his own drugstore. The business climate in Oswego was poor, so he moved his family to Condon in 1905.

In 1909, Pauling's grandfather, Linus, divorced his second wife and married a young schoolteacher who was almost the same age as his daughter Lucy. A few months later, he died of a heart attack, brought on by complications from nephritis
Nephritis
Nephritis is inflammation of the nephrons in the kidneys. The word "nephritis" was imported from Latin, which took it from Greek: νεφρίτιδα. The word comes from the Greek νεφρός - nephro- meaning "of the kidney" and -itis meaning "inflammation"....

. Meanwhile, Herman Pauling was suffering from poor health and had regular sharp pains in his abdomen
Abdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...

. Lucy's sister, Abbie, saw that Herman was dying and immediately called the family physician. The doctor gave Herman a sedative to reduce the pain, but it only offered temporary relief. His health worsened in the coming months and he finally died of a perforated ulcer
Peptic ulcer
A peptic ulcer, also known as PUD or peptic ulcer disease, is the most common ulcer of an area of the gastrointestinal tract that is usually acidic and thus extremely painful. It is defined as mucosal erosions equal to or greater than 0.5 cm...

 on June 11, 1910, leaving Lucy to care for Linus, Lucile and Pauline.

At age nine, Linus was a voracious reader as a child. On May 12, 1910 his father wrote a letter to The Oregonian
The Oregonian
The Oregonian is the major daily newspaper in Portland, Oregon, owned by Advance Publications. It is the oldest continuously published newspaper on the U.S. west coast, founded as a weekly by Thomas J. Dryer on December 4, 1850...

inviting suggestions of additional books to occupy his time. Pauling first planned to become a chemist after being amazed by experiments conducted with a small chemistry lab kit by his friend, Lloyd A. Jeffress. At high school, Pauling continued to conduct chemistry experiments, scavenging much of the equipment and material from an abandoned steel plant. With an older friend, Lloyd Simon, Pauling set up Palmon Laboratories. Operating from Simon's basement, the two approached local dairies to offer their services in performing butterfat samplings at cheap prices. Dairymen were wary of trusting two boys with the task, and as such, the business ended in failure.

By the fall of 1916, Pauling was a 15-year-old high school senior with enough credits to enter Oregon State University
Oregon State University
Oregon State University is a coeducational, public research university located in Corvallis, Oregon, United States. The university offers undergraduate, graduate and doctoral degrees and a multitude of research opportunities. There are more than 200 academic degree programs offered through the...

 (OSU), known then as Oregon Agricultural College. He did not have enough credits for two required American history courses that would satisfy the requirements for earning a high school diploma
High school diploma
A high school diploma is a diploma awarded for the completion of high school. In the United States and Canada, it is considered the minimum education required for government jobs and higher education. An equivalent is the GED.-Past diploma styles:...

. He asked the school principal if he could take these courses concurrently during the spring semester, but the principal denied his request, and Pauling decided to leave the school in June without a diploma. His high school, Washington High School
Washington High School (Portland, Oregon)
Washington High School was a high school in Portland, Oregon, United States, described in 1950 as "Portland's finest high school." It was part of the Portland school district. Opened in September 1906, the school was originally named the East Side High School, but changed its name to Washington in...

 in Portland, awarded him the diploma 45 years later, after he had won two Nobel Prizes. During the summer, Pauling worked part-time at a grocery store, earning eight dollars a week. His mother set him up with an interview with a Mr Schwietzerhoff, the owner of a number of manufacturing plants in Portland. Pauling was hired as an apprentice machinist with a salary of 40 dollars a month. Pauling excelled at his job, and saw his salary soon raised to 50 dollars a month. In his spare time, he set up a photography laboratory with two friends and found business from a local photography company. He hoped that the business would earn him enough money to pay for his future college expenses. Pauling received a letter of admission from OAC in September 1917 and immediately gave notice
Resignation
A resignation is the formal act of giving up or quitting one's office or position. It can also refer to the act of admitting defeat in a game like chess, indicated by the resigning player declaring "I resign", turning his king on its side, extending his hand, or stopping the chess clock...

 to his boss and told his mother of his plans.

Higher education


In October 1917, Pauling lived in a boarding house
Boarding house
A boarding house, is a house in which lodgers rent one or more rooms for one or more nights, and sometimes for extended periods of weeks, months and years. The common parts of the house are maintained, and some services, such as laundry and cleaning, may be supplied. They normally provide "bed...

 on the Corvallis
Corvallis, Oregon
Corvallis is a city located in central western Oregon, United States. It is the county seat of Benton County and the principal city of the Corvallis, Oregon Metropolitan Statistical Area, which encompasses all of Benton County. As of the 2010 United States Census, the population was 54,462....

 campus with his cousin Mervyn and another man, using the $200 he had saved from odd jobs to finance his education. In his first semester, Pauling registered for two courses in chemistry, two in mathematics, mechanical drawing, introduction to mining and use of explosives, modern English prose, gymnastics and military drill. Pauling fell in love with a freshman girl named Irene early in the school year. By the end of October, he had used up $150 of his savings on her, taking her to shows and games. He soon got a job at the girls' dormitory, working 100 hours a month chopping wood for stoves, cutting up beef and mopping up the kitchen. Despite the salary of 25 cents per hour, Pauling was still having trouble managing his finances. He began eating one hot meal a day at a restaurant off campus to keep his expenses down. Pauling was active in campus life and founded the school's chapter of the Delta Upsilon
Delta Upsilon
Delta Upsilon is the sixth oldest international, all-male, college Greek-letter organization, and is the oldest non-secret fraternity in North America...

 fraternity. After his second year, he planned to take a job in Portland to help support his mother, but the college offered him a position teaching quantitative analysis
Quantitative analysis (chemistry)
In chemistry, quantitative analysis is the determination of the absolute or relative abundance of one, several or all particular substance present in a sample....

, a course he had just finished taking himself. He worked forty hours a week in the laboratory and classroom and earned $100 a month. This allowed him to continue his studies at the college.

In his last two years at school, Pauling became aware of the work of Gilbert N. Lewis
Gilbert N. Lewis
Gilbert Newton Lewis was an American physical chemist known for the discovery of the covalent bond , his purification of heavy water, his reformulation of chemical thermodynamics in a mathematically rigorous manner accessible to ordinary chemists, his theory of Lewis acids and...

 and Irving Langmuir
Irving Langmuir
Irving Langmuir was an American chemist and physicist. His most noted publication was the famous 1919 article "The Arrangement of Electrons in Atoms and Molecules" in which, building on Gilbert N. Lewis's cubical atom theory and Walther Kossel's chemical bonding theory, he outlined his...

 on the electronic structure of atom
Atom
The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...

s and their bonding
Chemical bond
A chemical bond is an attraction between atoms that allows the formation of chemical substances that contain two or more atoms. The bond is caused by the electromagnetic force attraction between opposite charges, either between electrons and nuclei, or as the result of a dipole attraction...

 to form molecule
Molecule
A molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...

s. He decided to focus his research on how the physical
Physical property
A physical property is any property that is measurable whose value describes a physical system's state. The changes in the physical properties of a system can be used to describe its transformations ....

 and chemical properties
Chemical property
A chemical property is any of a material's properties that becomes evident during a chemical reaction; that is, any quality that can be established only by changing a substance's chemical identity...

 of substances are related to the structure of the atoms of which they are composed, becoming one of the founders of the new science of quantum chemistry. Pauling began to neglect his studies in humanities and social sciences. He had also exhausted the course offerings in the physics and mathematics departments. Professor Samuel Graf selected Pauling to be his teaching assistant in a high-level mathematics course. During the winter of his senior year, Pauling was approached by the college to teach a chemistry course for home economics
Family and consumer science
Family and consumer sciences is an academic discipline that combines aspects of social and natural science. Family and consumer sciences deals with the relationship between individuals, families, and communities, and the environment in which they live...

 majors. It was in one of these classes that Pauling met his future wife, Ava Helen Miller
Ava Helen Pauling
Ava Helen Pauling was an American human rights activist and wife of Nobel Prize winner Linus Pauling. Throughout her life, she was involved in various social movements including women's rights, racial equality, and international peace.An avid New Dealer, Ava Helen Pauling was heavily interested...

.

In 1922, Pauling graduated from Oregon State University
Oregon State University
Oregon State University is a coeducational, public research university located in Corvallis, Oregon, United States. The university offers undergraduate, graduate and doctoral degrees and a multitude of research opportunities. There are more than 200 academic degree programs offered through the...

 with a degree in chemical engineering
Chemical engineering
Chemical engineering is the branch of engineering that deals with physical science , and life sciences with mathematics and economics, to the process of converting raw materials or chemicals into more useful or valuable forms...

 and went on to graduate school
Graduate school
A graduate school is a school that awards advanced academic degrees with the general requirement that students must have earned a previous undergraduate degree...

 at the California Institute of Technology
California Institute of Technology
The California Institute of Technology is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering...

 (Caltech) in Pasadena, California
Pasadena, California
Pasadena is a city in Los Angeles County, California, United States. Although famous for hosting the annual Rose Bowl football game and Tournament of Roses Parade, Pasadena is the home to many scientific and cultural institutions, including the California Institute of Technology , the Jet...

, under the guidance of Roscoe G. Dickinson
Roscoe G. Dickinson
Roscoe Gilkey Dickinson was a U.S. chemist, known primarily for his work on X-ray crystallography. As professor of chemistry at the California Institute of Technology , he was the doctoral advisor of Nobel laureate Linus Pauling and of Arnold O...

. His graduate research involved the use of X-ray diffraction to determine the structure of crystal
Crystal
A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is known as crystallography...

s. He published seven papers on the crystal structure
Crystal structure
In mineralogy and crystallography, crystal structure is a unique arrangement of atoms or molecules in a crystalline liquid or solid. A crystal structure is composed of a pattern, a set of atoms arranged in a particular way, and a lattice exhibiting long-range order and symmetry...

 of mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...

s while he was at Caltech. He received his Ph. D.
Doctor of Philosophy
Doctor of Philosophy, abbreviated as Ph.D., PhD, D.Phil., or DPhil , in English-speaking countries, is a postgraduate academic degree awarded by universities...

 in physical chemistry
Physical chemistry
Physical chemistry is the study of macroscopic, atomic, subatomic, and particulate phenomena in chemical systems in terms of physical laws and concepts...

 and mathematical physics
Mathematical physics
Mathematical physics refers to development of mathematical methods for application to problems in physics. The Journal of Mathematical Physics defines this area as: "the application of mathematics to problems in physics and the development of mathematical methods suitable for such applications and...

, summa cum laude, in 1925.

Personal life


While teaching a class called "Chemistry for Home Economic Majors" at college, Pauling met his future wife, Ava Helen Miller
Ava Helen Pauling
Ava Helen Pauling was an American human rights activist and wife of Nobel Prize winner Linus Pauling. Throughout her life, she was involved in various social movements including women's rights, racial equality, and international peace.An avid New Dealer, Ava Helen Pauling was heavily interested...

 and they married June 17th, 1923. The marriage would last until 1981 upon Ava Pauling's death, and produce three sons (Linus Jr., Peter and Edward Crellin) and a daughter (Linda). Pauling's sons went on to become scientists and researchers (Linus a psychiatrist
Psychiatry
Psychiatry is the medical specialty devoted to the study and treatment of mental disorders. These mental disorders include various affective, behavioural, cognitive and perceptual abnormalities...

, Peter, who died in 2003 a crystallographer
Crystallography
Crystallography is the experimental science of the arrangement of atoms in solids. The word "crystallography" derives from the Greek words crystallon = cold drop / frozen drop, with its meaning extending to all solids with some degree of transparency, and grapho = write.Before the development of...

, and Edward Crellin, who died in 1997, a biologist
Biology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...

; Linda married a geologist
Geology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...

).

Pauling was raised as a member of the Lutheran Church, but later joined the Unitarian Universalist Church and publicly declared his atheism
Atheism
Atheism is, in a broad sense, the rejection of belief in the existence of deities. In a narrower sense, atheism is specifically the position that there are no deities...

 two years before his death.

Career


Pauling was first exposed to the concepts of quantum mechanics
Quantum mechanics
Quantum mechanics, also known as quantum physics or quantum theory, is a branch of physics providing a mathematical description of much of the dual particle-like and wave-like behavior and interactions of energy and matter. It departs from classical mechanics primarily at the atomic and subatomic...

 while studying at Oregon State University
Oregon State University
Oregon State University is a coeducational, public research university located in Corvallis, Oregon, United States. The university offers undergraduate, graduate and doctoral degrees and a multitude of research opportunities. There are more than 200 academic degree programs offered through the...

. He later traveled to Europe on a Guggenheim Fellowship
Guggenheim Fellowship
Guggenheim Fellowships are American grants that have been awarded annually since 1925 by the John Simon Guggenheim Memorial Foundation to those "who have demonstrated exceptional capacity for productive scholarship or exceptional creative ability in the arts." Each year, the foundation makes...

, which was awarded to him in 1926, to study under German physicist Arnold Sommerfeld
Arnold Sommerfeld
Arnold Johannes Wilhelm Sommerfeld was a German theoretical physicist who pioneered developments in atomic and quantum physics, and also educated and groomed a large number of students for the new era of theoretical physics...

 in Munich
Munich
Munich The city's motto is "" . Before 2006, it was "Weltstadt mit Herz" . Its native name, , is derived from the Old High German Munichen, meaning "by the monks' place". The city's name derives from the monks of the Benedictine order who founded the city; hence the monk depicted on the city's coat...

, Danish physicist Niels Bohr
Niels Bohr
Niels Henrik David Bohr was a Danish physicist who made foundational contributions to understanding atomic structure and quantum mechanics, for which he received the Nobel Prize in Physics in 1922. Bohr mentored and collaborated with many of the top physicists of the century at his institute in...

 in Copenhagen
Copenhagen
Copenhagen is the capital and largest city of Denmark, with an urban population of 1,199,224 and a metropolitan population of 1,930,260 . With the completion of the transnational Øresund Bridge in 2000, Copenhagen has become the centre of the increasingly integrating Øresund Region...

 and Austrian physicist Erwin Schrödinger
Erwin Schrödinger
Erwin Rudolf Josef Alexander Schrödinger was an Austrian physicist and theoretical biologist who was one of the fathers of quantum mechanics, and is famed for a number of important contributions to physics, especially the Schrödinger equation, for which he received the Nobel Prize in Physics in 1933...

 in Zürich
Zürich
Zurich is the largest city in Switzerland and the capital of the canton of Zurich. It is located in central Switzerland at the northwestern tip of Lake Zurich...

. All three were experts in the new field of quantum mechanics and other branches of physics. Pauling became interested in how quantum mechanics might be applied in his chosen field of interest, the electronic structure
Electron configuration
In atomic physics and quantum chemistry, electron configuration is the arrangement of electrons of an atom, a molecule, or other physical structure...

 of atom
Atom
The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...

s and molecule
Molecule
A molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...

s. In Zürich, Pauling was also exposed to one of the first quantum mechanical analyses of bonding in the hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 molecule, done by Walter Heitler
Walter Heitler
Walter Heinrich Heitler was a German physicist who made contributions to quantum electrodynamics and quantum field theory...

 and Fritz London
Fritz London
Fritz Wolfgang London was a German theoretical physicist. His fundamental contributions to the theories of chemical bonding and of intermolecular forces are today considered classic and are discussed in standard textbooks of physical chemistry.With his brother Heinz, he made a significant...

. Pauling devoted the two years of his European trip to this work and decided to make it the focus of his future research. He became one of the first scientists in the field of quantum chemistry and a pioneer in the application of quantum theory to the structure of molecules. He also joined Alpha Chi Sigma
Alpha Chi Sigma
Alpha Chi Sigma is a professional fraternity specializing in the field of chemistry. It has both collegiate and professional chapters throughout the United States consisting of both men and women and numbering more than 63,400 members...

, the professional chemistry fraternity.

In 1927, Pauling took a new position as an assistant professor at Caltech in theoretical chemistry
Theoretical chemistry
Theoretical chemistry seeks to provide theories that explain chemical observations. Often, it uses mathematical and computational methods that, at times, require advanced knowledge. Quantum chemistry, the application of quantum mechanics to the understanding of valency, is a major component of...

. He launched his faculty career with a very productive five years, continuing with his X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...

 crystal studies and also performing quantum mechanical calculations on atoms and molecules. He published approximately fifty papers in those five years, and created five rules now known as Pauling's rules
Pauling's rules
Pauling's rules are five rules published by Linus Pauling in 1929 for determining the crystal structures of complex ionic crystals.-First rule:...

. By 1929, he was promoted to associate professor, and by 1930, to full professor. In 1931, the American Chemical Society
American Chemical Society
The American Chemical Society is a scientific society based in the United States that supports scientific inquiry in the field of chemistry. Founded in 1876 at New York University, the ACS currently has more than 161,000 members at all degree-levels and in all fields of chemistry, chemical...

 awarded Pauling the Langmuir Prize
Irving Langmuir
Irving Langmuir was an American chemist and physicist. His most noted publication was the famous 1919 article "The Arrangement of Electrons in Atoms and Molecules" in which, building on Gilbert N. Lewis's cubical atom theory and Walther Kossel's chemical bonding theory, he outlined his...

 for the most significant work in pure science by a person 30 years of age or younger. The following year, Pauling published what he regarded as his most important paper, in which he first laid out the concept of hybridization of atomic orbitals and analyzed the tetravalency
Tetravalence
In chemistry, a tetravalence is the state of an atom with four electrons available for covalent chemical bonding in its valence . An example is methane : the tetravalent carbon atom forms a covalent bond with four hydrogen atoms...

 of the carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...

 atom.

At Caltech, Pauling struck up a close friendship with theoretical physicist
Theoretical physics
Theoretical physics is a branch of physics which employs mathematical models and abstractions of physics to rationalize, explain and predict natural phenomena...

 Robert Oppenheimer
Robert Oppenheimer
Julius Robert Oppenheimer was an American theoretical physicist and professor of physics at the University of California, Berkeley. Along with Enrico Fermi, he is often called the "father of the atomic bomb" for his role in the Manhattan Project, the World War II project that developed the first...

, who was spending part of his research and teaching schedule away from U.C. Berkeley
University of California, Berkeley
The University of California, Berkeley , is a teaching and research university established in 1868 and located in Berkeley, California, USA...

 at Caltech every year. The two men planned to mount a joint attack on the nature of the chemical bond: apparently Oppenheimer would supply the mathematics and Pauling would interpret the results. Their relationship soured when Pauling began to suspect that Oppenheimer was becoming too close to his wife, Ava Helen. Once, when Pauling was at work, Oppenheimer had come to their place and blurted out an invitation to Ava Helen to join him on a tryst in Mexico. She flatly refused, and reported the incident to Pauling. Disquieted by this strange chemistry, and her apparent nonchalance about the incident, he immediately cut off his relationship with Oppenheimer.

In the summer of 1930, Pauling made another European trip, during which he learned about the use of electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...

s in diffraction
Diffraction
Diffraction refers to various phenomena which occur when a wave encounters an obstacle. Italian scientist Francesco Maria Grimaldi coined the word "diffraction" and was the first to record accurate observations of the phenomenon in 1665...

 studies similar to the ones he had performed with X-rays. After returning, he built an electron diffraction
Electron diffraction
Electron diffraction refers to the wave nature of electrons. However, from a technical or practical point of view, it may be regarded as a technique used to study matter by firing electrons at a sample and observing the resulting interference pattern...

 instrument at Caltech with a student of his, L. O. Brockway, and used it to study the molecular structure
Molecular geometry
Molecular geometry or molecular structure is the three-dimensional arrangement of the atoms that constitute a molecule. It determines several properties of a substance including its reactivity, polarity, phase of matter, color, magnetism, and biological activity.- Molecular geometry determination...

 of a large number of chemical substances.

Pauling introduced the concept of electronegativity
Electronegativity
Electronegativity, symbol χ , is a chemical property that describes the tendency of an atom or a functional group to attract electrons towards itself. An atom's electronegativity is affected by both its atomic number and the distance that its valence electrons reside from the charged nucleus...

 in 1932. Using the various properties of molecule
Molecule
A molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...

s, such as the energy required to break bonds and the dipole
Dipole
In physics, there are several kinds of dipoles:*An electric dipole is a separation of positive and negative charges. The simplest example of this is a pair of electric charges of equal magnitude but opposite sign, separated by some distance. A permanent electric dipole is called an electret.*A...

 moments
Moment (physics)
In physics, the term moment can refer to many different concepts:*Moment of force is the tendency of a force to twist or rotate an object; see the article torque for details. This is an important, basic concept in engineering and physics. A moment is valued mathematically as the product of the...

 of molecules, he established a scale and an associated numerical value for most of the elements — the Pauling Electronegativity Scale — which is useful in predicting the nature of bonds between atoms in molecules.

Activism


Pauling had been practically apolitical until World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

, but the aftermath of the war and his wife's pacifism changed his life profoundly, and he became a peace activist. During the beginning of the Manhattan Project
Manhattan Project
The Manhattan Project was a research and development program, led by the United States with participation from the United Kingdom and Canada, that produced the first atomic bomb during World War II. From 1942 to 1946, the project was under the direction of Major General Leslie Groves of the US Army...

, Robert Oppenheimer
Robert Oppenheimer
Julius Robert Oppenheimer was an American theoretical physicist and professor of physics at the University of California, Berkeley. Along with Enrico Fermi, he is often called the "father of the atomic bomb" for his role in the Manhattan Project, the World War II project that developed the first...

 invited him to be in charge of the Chemistry division of the project, but he declined, not wanting to uproot his family. He did work on other projects that had military applications, such as explosives, rocket propellants, an oxygen meter for submarines and the patent of an armor-piercing shell; he was awarded a Presidential Medal of Merit. In 1946, he joined the Emergency Committee of Atomic Scientists
Emergency Committee of Atomic Scientists
The Emergency Committee of Atomic Scientists was founded by Albert Einstein and Leó Szilárd in 1946. Its aims were to warn the public of the dangers associated with the development of nuclear weapons, promote the peaceful use of nuclear energy, and ultimately work towards world peace, which was...

, chaired by Albert Einstein
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...

. Its mission was to warn the public of the dangers associated with the development of nuclear weapons. His political activism prompted the U.S. State Department
United States Department of State
The United States Department of State , is the United States federal executive department responsible for international relations of the United States, equivalent to the foreign ministries of other countries...

 to deny him a passport
Passport
A passport is a document, issued by a national government, which certifies, for the purpose of international travel, the identity and nationality of its holder. The elements of identity are name, date of birth, sex, and place of birth....

 in 1952, when he was invited to speak at a scientific conference in London. His passport was restored in 1954, shortly before the ceremony in Stockholm
Stockholm
Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...

 where he received his first Nobel Prize. Joining Einstein, Bertrand Russell
Bertrand Russell
Bertrand Arthur William Russell, 3rd Earl Russell, OM, FRS was a British philosopher, logician, mathematician, historian, and social critic. At various points in his life he considered himself a liberal, a socialist, and a pacifist, but he also admitted that he had never been any of these things...

 and eight other leading scientists and intellectuals, he signed the Russell-Einstein Manifesto
Russell-Einstein Manifesto
The Russell–Einstein Manifesto was issued in London on July 9, 1955 by Bertrand Russell in the midst of the Cold War. It highlighted the dangers posed by nuclear weapons and called for world leaders to seek peaceful resolutions to international conflict...

 in 1955.

In 1958, Pauling joined a petition drive in cooperation with the founders of the St. Louis Citizen's Committee for Nuclear Information (CNI). This group, headed by Washington University professors Barry Commoner
Barry Commoner
Barry Commoner is an American biologist, college professor, and eco-socialist. He ran for president of the United States in the 1980 US presidential election on the Citizens Party ticket. He was also editor of Science Illustrated magazine.-Biography:Commoner was born in Brooklyn...

, Eric Reiss, M. W. Friedlander and John Fowler, set up a study of radioactive strontium
Strontium
Strontium is a chemical element with the symbol Sr and the atomic number 38. An alkaline earth metal, strontium is a soft silver-white or yellowish metallic element that is highly reactive chemically. The metal turns yellow when exposed to air. It occurs naturally in the minerals celestine and...

-90 in the baby teeth of children across North America. The "Baby Tooth Survey
Baby Tooth Survey
The Baby Tooth Survey was initiated by the Greater St. Louis Citizens' Committee for Nuclear Information in conjunction with Saint Louis University and the Washington University School of Dental Medicine as a means of determining the effects of nuclear fallout in the human anatomy by examining the...

," headed by Dr Louise Reiss
Louise Reiss
Louise Marie Zibold Reiss was an American physician who coordinated what became known as the Baby Tooth Survey, in which deciduous teeth from children living in the St. Louis, Missouri area who were born in the 1950s and 1960s were collected and analyzed over a period of 12 years...

, demonstrated conclusively in 1961 that above-ground nuclear testing posed significant public health risks in the form of radioactive fallout
Nuclear fallout
Fallout is the residual radioactive material propelled into the upper atmosphere following a nuclear blast, so called because it "falls out" of the sky after the explosion and shock wave have passed. It commonly refers to the radioactive dust and ash created when a nuclear weapon explodes...

 spread primarily via milk from cows that had ingested contaminated grass. Pauling also participated in a public debate with the atomic physicist Edward Teller
Edward Teller
Edward Teller was a Hungarian-American theoretical physicist, known colloquially as "the father of the hydrogen bomb," even though he did not care for the title. Teller made numerous contributions to nuclear and molecular physics, spectroscopy , and surface physics...

 about the actual probability of fallout causing mutations. In 1958, Pauling and his wife presented the United Nations
United Nations
The United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and achievement of world peace...

 with the petition signed by more than 11,000 scientists calling for an end to nuclear-weapon testing
Nuclear testing
Nuclear weapons tests are experiments carried out to determine the effectiveness, yield and explosive capability of nuclear weapons. Throughout the twentieth century, most nations that have developed nuclear weapons have tested them...

. Public pressure and the frightening results of the CNI research subsequently led to a moratorium on above-ground nuclear weapons testing, followed by the Partial Test Ban Treaty
Partial Test Ban Treaty
The treaty banning nuclear weapon tests in the atmosphere, in outer space and under water, often abbreviated as the Partial Test Ban Treaty , Limited Test Ban Treaty , or Nuclear Test Ban Treaty is a treaty prohibiting all test detonations of nuclear weapons...

, signed in 1963 by John F. Kennedy
John F. Kennedy
John Fitzgerald "Jack" Kennedy , often referred to by his initials JFK, was the 35th President of the United States, serving from 1961 until his assassination in 1963....

 and Nikita Khrushchev
Nikita Khrushchev
Nikita Sergeyevich Khrushchev led the Soviet Union during part of the Cold War. He served as First Secretary of the Communist Party of the Soviet Union from 1953 to 1964, and as Chairman of the Council of Ministers, or Premier, from 1958 to 1964...

. On the day that the treaty went into force, the Nobel Prize Committee awarded Pauling the Nobel Peace Prize
Nobel Peace Prize
The Nobel Peace Prize is one of the five Nobel Prizes bequeathed by the Swedish industrialist and inventor Alfred Nobel.-Background:According to Nobel's will, the Peace Prize shall be awarded to the person who...

, describing him as "Linus Carl Pauling, who ever since 1946 has campaigned ceaselessly, not only against nuclear weapons tests, not only against the spread of these armaments, not only against their very use, but against all warfare as a means of solving international conflicts." The Committee for Nuclear Information was never credited for its significant contribution to the test ban, nor was the ground-breaking research conducted by Dr Reiss and the "Baby Tooth Survey". The Caltech Chemistry Department, wary of his political views, did not even formally congratulate him. They did throw him a small party, showing they were more appreciative and sympathetic toward his work on radiation mutation. At Caltech he founded Sigma Xi
Sigma Xi
Sigma Xi: The Scientific Research Society is a non-profit honor society which was founded in 1886 at Cornell University by a junior faculty member and a handful of graduate students. Members elect others on the basis of their research achievements or potential...

's (The Scientific Research Society) chapter at the school, as he had previously been a member of that organisation. He continued his peace activism in the following years co-founding the International League of Humanists
International League of Humanists
International League of Humanists is a non-profit international association of eminent humanists. Its headquarters are in Sarajevo, Bosnia and Herzegovina and its primary objective is promotion of worldwide peace and human rights...

 in 1974. He was president of the scientific advisory board of the World Union for Protection of Life
World Union for Protection of Life
The World Union for Protection of Life is an international non-profit organization and non-governmental organization which was founded 1958 in Salzburg by the writer Günther Schwab...

 and also one of the signatories of the Dubrovnik-Philadelphia Statement.

Many of Pauling's critics, including scientists who appreciated the contributions that he had made in chemistry, disagreed with his political positions and saw him as a naive spokesman for Soviet communism
Communist Party of the Soviet Union
The Communist Party of the Soviet Union was the only legal, ruling political party in the Soviet Union and one of the largest communist organizations in the world...

. He was ordered to appear before the Senate Internal Security Subcommittee
United States Senate Subcommittee on Internal Security
The Special Subcommittee to Investigate the Administration of the Internal Security Act and Other Internal Security Laws, 1951-77, more commonly known as the Senate Internal Security Subcommittee and sometimes the McCarran Committee, was authorized under S...

, which termed him "the number one scientific name in virtually every major activity of the Communist peace offensive in this country." A headline in Life magazine characterized his 1962 Nobel Prize as "A Weird Insult from Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

". Pauling was awarded the International Lenin Peace Prize
Lenin Peace Prize
The International Lenin Peace Prize was the Soviet Union's equivalent to the Nobel Peace Prize, named in honor of Vladimir Lenin. It was awarded by a panel appointed by the Soviet government, to notable individuals whom the panel indicated had "strengthened peace among peoples"...

 by the USSR in 1970.

Biological molecules



In the mid-1930s, Pauling, strongly influenced by the biologically oriented funding priorities of the Rockefeller Foundation's Warren Weaver
Warren Weaver
Warren Weaver was an American scientist, mathematician, and science administrator...

, decided to strike out into new areas of interest. Although Pauling's early interest had focused almost exclusively on inorganic molecular structures, he had occasionally thought about molecules of biological
Biology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...

 importance, in part because of Caltech's growing strength in biology. Pauling interacted with such great biologists as Thomas Hunt Morgan
Thomas Hunt Morgan
Thomas Hunt Morgan was an American evolutionary biologist, geneticist and embryologist and science author who won the Nobel Prize in Physiology or Medicine in 1933 for discoveries relating the role the chromosome plays in heredity.Morgan received his PhD from Johns Hopkins University in zoology...

, Theodosius Dobzhanski, Calvin Bridges
Calvin Bridges
Calvin Blackman Bridges was an American scientist, known for his contributions to the field of genetics. Along with Alfred Sturtevant and H.J. Muller, Bridges was part of the famous fly room of Thomas Hunt Morgan at Columbia University.Bridges wrote a masterful Ph.D...

 and Alfred Sturtevant
Alfred Sturtevant
Alfred Henry Sturtevant was an American geneticist. Sturtevant constructed the first genetic map of a chromosome in 1913. Throughout his career he worked on the organism Drosophila melanogaster with Thomas Hunt Morgan...

. His early work in this area included studies of the structure of hemoglobin
Hemoglobin
Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates...

. He demonstrated that the hemoglobin molecule changes structure when it gains or loses an oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 atom. As a result of this observation, he decided to conduct a more thorough study of protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 structure in general. He returned to his earlier use of X-ray diffraction analysis. But protein structures were far less amenable to this technique than the crystal
Crystal
A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is known as crystallography...

line mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...

s of his former work. The best X-ray pictures of proteins in the 1930s had been made by the British crystallographer
Crystallography
Crystallography is the experimental science of the arrangement of atoms in solids. The word "crystallography" derives from the Greek words crystallon = cold drop / frozen drop, with its meaning extending to all solids with some degree of transparency, and grapho = write.Before the development of...

 William Astbury
William Astbury
William Thomas Astbury FRS was an English physicist and molecular biologist who made pioneering X-ray diffraction studies of biological molecules. His work on keratin provided the foundation for Linus Pauling's discovery of the alpha helix...

, but when Pauling tried, in 1937, to account for Astbury's observations quantum mechanically, he could not.

It took eleven years for Pauling to explain the problem: his mathematical
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

 analysis was correct, but Astbury's pictures were taken in such a way that the protein molecules were tilted from their expected positions. Pauling had formulated a model for the structure of hemoglobin
Hemoglobin
Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates...

 in which atoms were arranged in a helical
Helix
A helix is a type of smooth space curve, i.e. a curve in three-dimensional space. It has the property that the tangent line at any point makes a constant angle with a fixed line called the axis. Examples of helixes are coil springs and the handrails of spiral staircases. A "filled-in" helix – for...

 pattern, and applied this idea to proteins in general.

In 1951, based on the structures of amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

s and peptide
Peptide
Peptides are short polymers of amino acid monomers linked by peptide bonds. They are distinguished from proteins on the basis of size, typically containing less than 50 monomer units. The shortest peptides are dipeptides, consisting of two amino acids joined by a single peptide bond...

s and the planar nature of the peptide bond, Pauling, Robert Corey
Robert Corey
Robert Brainard Corey was an American biochemist, mostly known for his role in discovery of the α-helix and the β-sheet with Linus Pauling. Also working with Pauling was Herman Branson. Their discoveries were remarkably correct, with even the bond lengths being accurate until about 40 years later...

 and Herman Branson
Herman Branson
Herman Russell Branson was an African-American physicist, best known for his research on the alpha helix protein structure, and was also the president of two colleges.- Early life :...

 correctly proposed the alpha helix
Alpha helix
A common motif in the secondary structure of proteins, the alpha helix is a right-handed coiled or spiral conformation, in which every backbone N-H group donates a hydrogen bond to the backbone C=O group of the amino acid four residues earlier...

 and beta sheet
Beta sheet
The β sheet is the second form of regular secondary structure in proteins, only somewhat less common than the alpha helix. Beta sheets consist of beta strands connected laterally by at least two or three backbone hydrogen bonds, forming a generally twisted, pleated sheet...

 as the primary structural motifs in protein secondary structure
Secondary structure
In biochemistry and structural biology, secondary structure is the general three-dimensional form of local segments of biopolymers such as proteins and nucleic acids...

. This work exemplified Pauling's ability to think unconventionally; central to the structure was the unorthodox assumption that one turn of the helix may well contain a non-integral
Integer
The integers are formed by the natural numbers together with the negatives of the non-zero natural numbers .They are known as Positive and Negative Integers respectively...

 number of amino acid residues; for the alpha helix it is 3.7 amino acid residues per turn.

Pauling then proposed that deoxyribonucleic acid (DNA) was a triple helix
Triple helix
In geometry, a triple helix is a set of three congruent geometrical helices with the same axis, differing by a translation along the axis. Structures in the form of a triple helix include:* collagen helix...

; his model contained several basic mistakes, including a proposal of neutral phosphate groups, an idea that conflicted with the acidity of DNA. Sir Lawrence Bragg
William Lawrence Bragg
Sir William Lawrence Bragg CH OBE MC FRS was an Australian-born British physicist and X-ray crystallographer, discoverer of the Bragg law of X-ray diffraction, which is basic for the determination of crystal structure. He was joint winner of the Nobel Prize for Physics in 1915. He was knighted...

 had been disappointed that Pauling had won the race to find the alpha helix structure of proteins. Bragg's team had made a fundamental error in making their models of protein by not recognizing the planar nature of the peptide bond. When it was learned at the Cavendish Laboratory
Cavendish Laboratory
The Cavendish Laboratory is the Department of Physics at the University of Cambridge, and is part of the university's School of Physical Sciences. It was opened in 1874 as a teaching laboratory....

 that Pauling was working on molecular models of the structure of DNA, Watson and Crick were allowed to make a molecular model of DNA. They later benefited from unpublished data from Maurice Wilkins
Maurice Wilkins
Maurice Hugh Frederick Wilkins CBE FRS was a New Zealand-born English physicist and molecular biologist, and Nobel Laureate whose research contributed to the scientific understanding of phosphorescence, isotope separation, optical microscopy and X-ray diffraction, and to the development of radar...

 and Rosalind Franklin
Rosalind Franklin
Rosalind Elsie Franklin was a British biophysicist and X-ray crystallographer who made critical contributions to the understanding of the fine molecular structures of DNA, RNA, viruses, coal and graphite...

 at King's College
King's College London
King's College London is a public research university located in London, United Kingdom and a constituent college of the federal University of London. King's has a claim to being the third oldest university in England, having been founded by King George IV and the Duke of Wellington in 1829, and...

 which showed evidence for a helix and planar base stacking along the helix axis. Early in 1953 James D. Watson
James D. Watson
James Dewey Watson is an American molecular biologist, geneticist, and zoologist, best known as one of the co-discoverers of the structure of DNA in 1953 with Francis Crick...

 and Francis Crick
Francis Crick
Francis Harry Compton Crick OM FRS was an English molecular biologist, biophysicist, and neuroscientist, and most noted for being one of two co-discoverers of the structure of the DNA molecule in 1953, together with James D. Watson...

 proposed a correct structure for the DNA double helix. Pauling later cited several reasons to explain how he had been misled about the structure of DNA, among them misleading density data and the lack of high quality X-ray diffraction photographs. During the time Pauling was researching the problem, Rosalind Franklin
Rosalind Franklin
Rosalind Elsie Franklin was a British biophysicist and X-ray crystallographer who made critical contributions to the understanding of the fine molecular structures of DNA, RNA, viruses, coal and graphite...

 in England was creating the world's best images. They were key to Watson's and Crick's success. Pauling did not see them before devising his mistaken DNA structure, although his assistant Robert Corey
Robert Corey
Robert Brainard Corey was an American biochemist, mostly known for his role in discovery of the α-helix and the β-sheet with Linus Pauling. Also working with Pauling was Herman Branson. Their discoveries were remarkably correct, with even the bond lengths being accurate until about 40 years later...

 did see at least some of them, while taking Pauling's place at a summer 1952 protein conference in England. Pauling had been prevented from attending because his passport was withheld by the State Department on suspicion that he had Communist sympathies. This led to the legend that Pauling missed the structure of DNA because of the politics of the day (this was at the start of the McCarthy
McCarthyism
McCarthyism is the practice of making accusations of disloyalty, subversion, or treason without proper regard for evidence. The term has its origins in the period in the United States known as the Second Red Scare, lasting roughly from the late 1940s to the late 1950s and characterized by...

 period in the United States). Politics did not play a critical role. Not only did Corey see the images at the time, but Pauling himself regained his passport within a few weeks and toured English laboratories well before writing his DNA paper. He had ample opportunity to visit Franklin's lab and see her work, but chose not to.

Pauling also studied enzyme
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 reactions and was among the first to point out that enzymes bring about reactions by stabilizing the transition state
Transition state
The transition state of a chemical reaction is a particular configuration along the reaction coordinate. It is defined as the state corresponding to the highest energy along this reaction coordinate. At this point, assuming a perfectly irreversible reaction, colliding reactant molecules will always...

 of the reaction, a view which is central to understanding their mechanism of action. He was also among the first scientists to postulate that the binding of antibodies to antigens would be due to a complementarity between their structures. Along the same lines, with the physicist turned biologist Max Delbruck
Max Delbrück
Max Ludwig Henning Delbrück was a German-American biophysicist and Nobel laureate.-Biography:Delbrück was born in Berlin, German Empire...

, he wrote an early paper arguing that DNA replication
DNA replication
DNA replication is a biological process that occurs in all living organisms and copies their DNA; it is the basis for biological inheritance. The process starts with one double-stranded DNA molecule and produces two identical copies of the molecule...

 was likely to be due to complementarity
Complementarity (molecular biology)
In molecular biology, complementarity is a property of double-stranded nucleic acids such as DNA, as well as DNA:RNA duplexes. Each strand is complementary to the other in that the base pairs between them are non-covalently connected via two or three hydrogen bonds...

, rather than similarity, as suggested by a few researchers. This was made clear in the model of the structure of DNA that Watson and Crick discovered.

Molecular genetics


In November 1949, Linus Pauling, Harvey Itano
Harvey Itano
Harvey Akio Itano was an American biochemist best known for his work on the molecular basis of sickle cell anemia and other diseases...

, S. J. Singer and Ibert Wells published "Sickle Cell Anemia, a Molecular Disease
Sickle Cell Anemia, a Molecular Disease
"Sickle Cell Anemia, a Molecular Disease" is a 1949 scientific paper by Linus Pauling, Harvey A. Itano, Seymour J. Singer and Ibert C. Wells that established sickle-cell anemia as a genetic disease in which affected individuals have a different form of the metalloprotein hemoglobin in their blood...

" in the journal Science
Science
Science is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...

. It was the first proof of a human disease caused by an abnormal protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

, and sickle cell anemia became the first disease understood at the molecular level. Using electrophoresis
Electrophoresis
Electrophoresis, also called cataphoresis, is the motion of dispersed particles relative to a fluid under the influence of a spatially uniform electric field. This electrokinetic phenomenon was observed for the first time in 1807 by Reuss , who noticed that the application of a constant electric...

, they demonstrated that individuals with sickle cell disease had a modified form of hemoglobin
Hemoglobin
Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates...

 in their red blood cell
Red blood cell
Red blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system...

s, and that individuals with sickle cell trait
Sickle cell trait
Sickle cell trait describes a condition in which a person has one abnormal allele of the hemoglobin beta gene , but does not display the severe symptoms of sickle cell disease that occur in a person who has two copies of that allele...

 had both the normal and abnormal forms of hemoglobin. This was also the first demonstration that Mendelian inheritance
Mendelian inheritance
Mendelian inheritance is a scientific description of how hereditary characteristics are passed from parent organisms to their offspring; it underlies much of genetics...

 determined the specific physical properties of proteins, not simply their presence or absence-the dawn of molecular genetics
Molecular genetics
Molecular genetics is the field of biology and genetics that studies the structure and function of genes at a molecular level. The field studies how the genes are transferred from generation to generation. Molecular genetics employs the methods of genetics and molecular biology...

.

Molecular medicine and medical research



In 1941, at age 40, Pauling was diagnosed with Bright's disease
Bright's disease
Bright's disease is a historical classification of kidney diseases that would be described in modern medicine as acute or chronic nephritis. The term is no longer used, as diseases are now classified according to their more fully understood causes....

, a renal disease. Following the recommendations of Thomas Addis
Thomas Addis
Thomas Addis was a physician-scientist who made important contributions to the understanding of how blood clots. He was a pioneer in the field of nephrology, the branch of internal medicine that deals with diseases of the kidney...

, Pauling was able to control the disease with Addis' then unusual, low protein, salt-free diet and vitamin supplements.

In 1951, Pauling gave a lecture entitled, "Molecular Medicine". In the late 1950s, Pauling worked on the role of enzymes in brain function, believing that mental illness may be partly caused by enzyme dysfunction. In 1965 Pauling read Niacin
Niacin
"Niacin" redirects here. For the neo-fusion band, see Niacin .Niacin is an organic compound with the formula and, depending on the definition used, one of the forty to eighty essential human nutrients.Niacin is one of five vitamins associated with a pandemic deficiency disease: niacin deficiency...

 Therapy in Psychiatry
by Abram Hoffer and theorized vitamins might have important biochemical effects unrelated to their prevention of associated deficiency diseases. In 1968 Pauling published a brief paper in Science
Science (journal)
Science is the academic journal of the American Association for the Advancement of Science and is one of the world's top scientific journals....

 entitled "Orthomolecular psychiatry" that gave name and principle to the popular but controversial megavitamin therapy
Megavitamin therapy
Megavitamin therapy is the use of large doses of vitamins, often many times greater than the recommended dietary allowance in the attempt to prevent or treat diseases...

 movement of the 1970s. Pauling coined the term "orthomolecular" to refer to the practice of varying the concentration of substances normally present in the body to prevent and treat disease. His ideas formed the basis of orthomolecular medicine
Orthomolecular medicine
Orthomolecular medicine is a form of complementary and alternative medicine that seeks to maintain health and prevent or treat diseases by optimizing nutritional intake and/or prescribing supplements...

, which is not generally practiced by conventional medical professionals and has been strongly criticized.

Pauling's work on vitamin C
Vitamin C
Vitamin C or L-ascorbic acid or L-ascorbate is an essential nutrient for humans and certain other animal species. In living organisms ascorbate acts as an antioxidant by protecting the body against oxidative stress...

 in his later years generated much controversy. He was first introduced to the concept of high-dose vitamin C by biochemist Irwin Stone
Irwin Stone
Irwin Stone was an American biochemist, chemical engineer, and author. He was the first to use ascorbic acid in the food processing industry as a preservative, and originated and published the hypothesis that humans require much larger amounts of Vitamin C for optimal health than is necessary to...

 in 1966. After becoming convinced of its worth, Pauling took 3 grams of vitamin C every day to prevent colds. Excited by his own perceived results, he researched the clinical literature and published Vitamin C and the Common Cold
Vitamin C and the Common Cold
Vitamin C and the Common Cold is a popular book by Linus Pauling, first published in 1970, on vitamin C, its interactions with common cold and the role of vitamin C megadosage in human health. The book promoted the idea that taking large amounts of vitamin C could reduce the duration and severity...

in 1970. He began a long clinical collaboration with the British cancer surgeon Ewan Cameron in 1971 on the use of intravenous and oral vitamin C as cancer therapy for terminal patients. Cameron and Pauling wrote many technical papers and a popular book, Cancer and Vitamin C, that discussed their observations. Pauling made vitamin C popular with the public and eventually published two studies of a group of one hundred allegedly terminal
Terminal illness
Terminal illness is a medical term popularized in the 20th century to describe a disease that cannot be cured or adequately treated and that is reasonably expected to result in the death of the patient within a short period of time. This term is more commonly used for progressive diseases such as...

 patients that claimed vitamin C increased survival by as much as four times compared to untreated patients. A re-evaluation of the claims in 1982 found that the patient groups were not actually comparable, with the vitamin C group being less sick on entry to the study, and judged to be "terminal" much earlier than the comparison group. Later clinical trials conducted by the Mayo Clinic
Mayo Clinic
Mayo Clinic is a not-for-profit medical practice and medical research group specializing in treating difficult patients . Patients are referred to Mayo Clinic from across the U.S. and the world, and it is known for innovative and effective treatments. Mayo Clinic is known for being at the top of...

 also found that high-dose (10,000 mg) vitamin C was no better than placebo
Placebo
A placebo is a simulated or otherwise medically ineffectual treatment for a disease or other medical condition intended to deceive the recipient...

 at treating cancer and that there was no benefit to high-dose vitamin C. The failure of the clinical trials to demonstrate any benefit resulted in the conclusion that vitamin C was not effective in treating cancer; the medical establishment also concluded his claims that vitamin C could prevent colds was quackery
Quackery
Quackery is a derogatory term used to describe the promotion of unproven or fraudulent medical practices. Random House Dictionary describes a "quack" as a "fraudulent or ignorant pretender to medical skill" or "a person who pretends, professionally or publicly, to have skill, knowledge, or...

. Pauling denounced the conclusions of these studies and handling of the final study as "fraud and deliberate misrepresentation", and criticized the studies for using oral, rather than intravenous
Intravenous therapy
Intravenous therapy or IV therapy is the infusion of liquid substances directly into a vein. The word intravenous simply means "within a vein". Therapies administered intravenously are often called specialty pharmaceuticals...

 vitamin C (which was the dosing method used for the first ten days of Pauling's original study). Pauling also criticised the Mayo clinic studies because the controls were taking vitamin C during the trial, and because the duration of the treatment with vitamin C was short; Pauling advocates continued high dose vitamin C for the rest of the cancer patient's life whereas the Mayo clinic patients in the second trial were treated with vitamin C for a median of 2.5 months. The results were publicly debated at length with considerable acrimony between Pauling and Cameron, and Moertel (the lead author of the Mayo Clinic studies), with accusations of misconduct and scientific incompetence on both sides. Ultimately the negative findings of the Mayo Clinic studies ended general interest in vitamin C as a treatment for cancer. Despite this, Pauling continued to promote vitamin C for treating cancer and the common cold, working with The Institutes for the Achievement of Human Potential
The Institutes for The Achievement of Human Potential
The Institutes for The Achievement of Human Potential is a non-profit organization providing teaching programs and literature which it promotes as improving the health and neurological development of normal children and of children who have sustained a brain injury.Although the institute's programs...

 to use vitamin C in the treatment of brain-injured children. He later collaborated with the Canadian physician Abram Hoffer
Abram Hoffer
Abram Hoffer was a Canadian biochemist, physician and psychiatrist. Hoffer developed a theory that nutrition and vitamins may be effective treatments for schizophrenia...

 on a micronutrient regimen, including high-dose vitamin C, as adjunctive cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...

 therapy.

With Arthur B. Robinson
Arthur B. Robinson
Arthur B. Robinson is an American scientist and activist. He is the founder, president, and professor of chemistry at the Oregon Institute of Science and Medicine, which describes itself as a research institute that studies protein chemistry, nutrition, and predictive and preventive medicine...

 and another colleague, Pauling founded the Institute of Orthomolecular Medicine in Menlo Park, California, in 1973, which was soon renamed the Linus Pauling Institute
Linus Pauling Institute
The Linus Pauling Institute is a research institute located at Oregon State University with a focus on health maintenance. The mission statement of the institute is three-fold. First, to determine the functional roles of micronutrients and phytochemicals in promoting optimal health and to treat or...

 of Science and Medicine. Pauling directed research on vitamin C, but also continued his theoretical work in chemistry and physics until his death. In his last years, he became especially interested in the possible role of vitamin C in preventing atherosclerosis
Atherosclerosis
Atherosclerosis is a condition in which an artery wall thickens as a result of the accumulation of fatty materials such as cholesterol...

 and published three case reports on the use of lysine
Lysine
Lysine is an α-amino acid with the chemical formula HO2CCH4NH2. It is an essential amino acid, which means that the human body cannot synthesize it. Its codons are AAA and AAG....

 and vitamin C to relieve angina pectoris. In 1996, the Linus Pauling Institute moved from Palo Alto, California, to Corvallis, Oregon, to become part of Oregon State University, where it continues to conduct research on micronutrient
Micronutrient
Micronutrients are nutrients required by humans and other living things throughout life in small quantities to orchestrate a whole range of physiological functions, but which the organism itself cannot produce. For people, they include dietary trace minerals in amounts generally less than 100...

s, phytochemical
Phytochemical
Phytochemicals are biologically active chemical compounds that occur naturally in plants . Phytochemicals are the molecules responsible for the color and organoleptic properties . For example, the deep purple color of blueberries and the smell of garlic...

s (chemicals from plants), and other constituents of the diet in preventing and treating disease. Several researchers that had previously worked at the Linus Pauling Institute in Palo Alto, including the assistant director of research, moved on to form the Genetic Information Research Institute
Genetic Information Research Institute
The Genetic Information Research Institute is a non-profit institution that was founded in 1994 by Jerzy Jurka. The mission of the institute "is to understand biological processes which alter the genetic makeup of different organisms, as a basis for potential gene therapy and genome engineering...

.

In the view of the medical community at the time, Pauling's hypotheses about high dose vitamins went considerably beyond the evidence base available. More recent research has caused a re-evaluation of his work and the importance of vitamins to health.

Nature of the chemical bond


In the late 1920s Pauling began publishing papers on the nature of the chemical bond, leading to his famous textbook on the subject published in 1939. It is based primarily on his work in this area that he received the Nobel Prize in Chemistry
Nobel Prize in Chemistry
The Nobel Prize in Chemistry is awarded annually by the Royal Swedish Academy of Sciences to scientists in the various fields of chemistry. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895, awarded for outstanding contributions in chemistry, physics, literature,...

 in 1954 "for his research into the nature of the chemical bond and its application to the elucidation of the structure of complex substances". Pauling summarized his work on the chemical bond in The Nature of the Chemical Bond, one of the most influential chemistry books ever published. In the 30 years after its first edition was published in 1939, the book was cited more than 16,000 times. Even today, many modern scientific papers and articles in important journals cite this work, more than half a century after first publication.

Part of Pauling's work on the nature of the chemical bond led to his introduction of the concept of orbital hybridization. While it is normal to think of the electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...

s in an atom
Atom
The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...

 as being described by orbital
Atomic orbital
An atomic orbital is a mathematical function that describes the wave-like behavior of either one electron or a pair of electrons in an atom. This function can be used to calculate the probability of finding any electron of an atom in any specific region around the atom's nucleus...

s of types such as s and p, it turns out that in describing the bonding in molecule
Molecule
A molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...

s, it is better to construct functions that partake of some of the properties of each. Thus the one 2s and three 2p orbitals in a carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...

 atom can be combined to make four equivalent orbitals (called sp3 hybrid orbitals), which would be the appropriate orbitals to describe carbon compounds such as methane
Methane
Methane is a chemical compound with the chemical formula . It is the simplest alkane, the principal component of natural gas, and probably the most abundant organic compound on earth. The relative abundance of methane makes it an attractive fuel...

, or the 2s orbital may be combined with two of the 2p orbitals to make three equivalent orbitals (called sp2 hybrid orbitals), with the remaining 2p orbital unhybridized, which would be the appropriate orbitals to describe certain unsaturated
Alkene
In organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...

 carbon compounds such as ethylene
Ethylene
Ethylene is a gaseous organic compound with the formula . It is the simplest alkene . Because it contains a carbon-carbon double bond, ethylene is classified as an unsaturated hydrocarbon. Ethylene is widely used in industry and is also a plant hormone...

. Other hybridization schemes are also found in other types of molecules.

Another area which he explored was the relationship between ionic bond
Ionic bond
An ionic bond is a type of chemical bond formed through an electrostatic attraction between two oppositely charged ions. Ionic bonds are formed between a cation, which is usually a metal, and an anion, which is usually a nonmetal. Pure ionic bonding cannot exist: all ionic compounds have some...

ing, where electron
Electron
The electron is a subatomic particle with a negative elementary electric charge. It has no known components or substructure; in other words, it is generally thought to be an elementary particle. An electron has a mass that is approximately 1/1836 that of the proton...

s are transferred between atom
Atom
The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...

s, and covalent bond
Covalent bond
A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding....

ing where electrons are shared between atoms on an equal basis. Pauling showed that these were merely extremes, between which most actual cases of bonding fall. It was here especially that Pauling's electronegativity
Electronegativity
Electronegativity, symbol χ , is a chemical property that describes the tendency of an atom or a functional group to attract electrons towards itself. An atom's electronegativity is affected by both its atomic number and the distance that its valence electrons reside from the charged nucleus...

concept was particularly useful; the electronegativity difference between a pair of atoms will be the surest predictor of the degree of ionicity of the bond.

The third of the topics that Pauling attacked under the overall heading of "the nature of the chemical bond" was the accounting of the structure of aromatic hydrocarbon
Aromatic hydrocarbon
An aromatic hydrocarbon or arene is a hydrocarbon with alternating double and single bonds between carbon atoms. The term 'aromatic' was assigned before the physical mechanism determining aromaticity was discovered, and was derived from the fact that many of the compounds have a sweet scent...

s, particularly the prototype, benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....

. The best description of benzene had been made by the German chemist Friedrich Kekulé
Friedrich August Kekulé von Stradonitz
Friedrich August Kekule von Stradonitz was a German organic chemist. From the 1850s until his death, Kekule was one of the most prominent chemists in Europe, especially in theoretical chemistry...

. He had treated it as a rapid interconversion between two structures, each with alternating single and double bond
Double bond
A double bond in chemistry is a chemical bond between two chemical elements involving four bonding electrons instead of the usual two. The most common double bond, that between two carbon atoms, can be found in alkenes. Many types of double bonds between two different elements exist, for example in...

s, but with the double bonds of one structure in the locations where the single bonds were in the other. Pauling showed that a proper description based on quantum mechanics was an intermediate structure which was a blend of each. The structure was a superposition of structures rather than a rapid interconversion between them. The name "resonance
Resonance (chemistry)
In chemistry, resonance or mesomerism is a way of describing delocalized electrons within certain molecules or polyatomic ions where the bonding cannot be expressed by one single Lewis formula...

" was later applied to this phenomenon. In a sense, this phenomenon resembles that of hybridization, described earlier, because it involves combining more than one electronic structure to achieve an intermediate result.

Structure of the atomic nucleus


On September 16, 1952, Pauling opened a new research notebook with these words "I have decided to attack the problem of the structure of nuclei." On October 15, 1965, Pauling published his Close-Packed Spheron Model of the atomic nucleus in two well respected journals, Science, and Proc. Natl. Acad. Sci.. For nearly three decades, until his death in 1994, Pauling published numerous papers on his spheron cluster model.

The basic idea behind Pauling's spheron model is that a nucleus can be viewed as a set of "clusters of nucleons". The basic nucleon clusters include the deuteron [np], helion
Helion (chemistry)
A helion is a short name for the naked nucleus of helium, a doubly positively charged helium ion. In practice, helion refers to the stable helium-3 nucleus, in opposition to the other stable nucleus helium-4, which is usually referred to as an alpha particle...

 [pnp], and triton
Tritium
Tritium is a radioactive isotope of hydrogen. The nucleus of tritium contains one proton and two neutrons, whereas the nucleus of protium contains one proton and no neutrons...

 [npn]. Even-even nuclei are described as being composed of clusters of alpha particle
Alpha particle
Alpha particles consist of two protons and two neutrons bound together into a particle identical to a helium nucleus, which is classically produced in the process of alpha decay, but may be produced also in other ways and given the same name...

s, as has often been done for light nuclei. Pauling attempted to derive the shell structure of nuclei from pure geometrical considerations related to Platonic solids rather than starting from an independent particle model as in the usual shell model
Shell model
In nuclear physics and nuclear chemistry, the nuclear shell model is a model of the atomic nucleus which uses the Pauli exclusion principle to describe the structure of the nucleus in terms of energy levels. The first shell model was proposed by Dmitry Ivanenko in 1932...

. In an interview given in 1990 Pauling commented on his model:

Legacy


Pauling died of prostate cancer
Prostate cancer
Prostate cancer is a form of cancer that develops in the prostate, a gland in the male reproductive system. Most prostate cancers are slow growing; however, there are cases of aggressive prostate cancers. The cancer cells may metastasize from the prostate to other parts of the body, particularly...

 on August 19, 1994, at 7:20 PM at home in Big Sur, California. He was 93 years old. A grave marker for him is in Oswego Pioneer Cemetery in Lake Oswego, Oregon
Lake Oswego, Oregon
Lake Oswego is a city located primarily in Clackamas County in the U.S. state of Oregon. Small portions of the city are also located in neighboring Multnomah and Washington counties. Located south of Portland surrounding the Oswego Lake, the town was founded in 1847 and incorporated as Oswego in...

.

Pauling was included in a list of the 20 greatest scientists of all time by the magazine New Scientist
New Scientist
New Scientist is a weekly non-peer-reviewed English-language international science magazine, which since 1996 has also run a website, covering recent developments in science and technology for a general audience. Founded in 1956, it is published by Reed Business Information Ltd, a subsidiary of...

, with Albert Einstein
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...

 being the only other scientist from the twentieth century on the list. Gautam R. Desiraju, the author of the Millennium Essay in Nature, claimed that Pauling was one of the greatest thinkers and visionaries of the millennium, along with Galileo, Newton, and Einstein. Pauling is notable for the diversity of his interests: quantum mechanics, inorganic chemistry, organic chemistry, protein structure, molecular biology, and medicine. In all these fields, and especially on the boundaries between them, he made decisive contributions. His work on chemical bonding marks the beginning of modern quantum chemistry, and many of his contributions like hybridization
Orbital hybridisation
In chemistry, hybridisation is the concept of mixing atomic orbitals to form new hybrid orbitals suitable for the qualitative description of atomic bonding properties. Hybridised orbitals are very useful in the explanation of the shape of molecular orbitals for molecules. It is an integral part...

 and electronegativity
Electronegativity
Electronegativity, symbol χ , is a chemical property that describes the tendency of an atom or a functional group to attract electrons towards itself. An atom's electronegativity is affected by both its atomic number and the distance that its valence electrons reside from the charged nucleus...

 have become part of standard chemistry textbooks. His valence bond approach fell short of accounting quantitatively for some of the characteristics of molecules, such as the paramagnetic nature of oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 and the color of organometallic complexes, and would later be superseded by the Molecular Orbital Theory
Molecular orbital theory
In chemistry, molecular orbital theory is a method for determining molecular structure in which electrons are not assigned to individual bonds between atoms, but are treated as moving under the influence of the nuclei in the whole molecule...

 of Robert Mulliken. The Valence Bond theory still exists in its modern form and competes with the Molecular Orbital Theory
Molecular orbital theory
In chemistry, molecular orbital theory is a method for determining molecular structure in which electrons are not assigned to individual bonds between atoms, but are treated as moving under the influence of the nuclei in the whole molecule...

 and Density Functional Theory
Density functional theory
Density functional theory is a quantum mechanical modelling method used in physics and chemistry to investigate the electronic structure of many-body systems, in particular atoms, molecules, and the condensed phases. With this theory, the properties of a many-electron system can be determined by...

 (DFT) for describing the chemical phenomena. Pauling's work on crystal
Crystal
A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is known as crystallography...

 structure contributed significantly to the prediction and elucidation of the structures of complex minerals and compounds. His discovery of the alpha helix
Alpha helix
A common motif in the secondary structure of proteins, the alpha helix is a right-handed coiled or spiral conformation, in which every backbone N-H group donates a hydrogen bond to the backbone C=O group of the amino acid four residues earlier...

 and beta sheet
Beta sheet
The β sheet is the second form of regular secondary structure in proteins, only somewhat less common than the alpha helix. Beta sheets consist of beta strands connected laterally by at least two or three backbone hydrogen bonds, forming a generally twisted, pleated sheet...

 is a fundamental foundation for the study of protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 structure.

Francis Crick
Francis Crick
Francis Harry Compton Crick OM FRS was an English molecular biologist, biophysicist, and neuroscientist, and most noted for being one of two co-discoverers of the structure of the DNA molecule in 1953, together with James D. Watson...

 acknowledged Pauling as the "father of molecular biology
Molecular biology
Molecular biology is the branch of biology that deals with the molecular basis of biological activity. This field overlaps with other areas of biology and chemistry, particularly genetics and biochemistry...

". His discovery of sickle cell anemia as a "molecular disease" opened the way toward examining genetically acquired mutations at a molecular level.

Pauling's work on the molecular basis of disease and its treatment is being carried on by a number of researchers, notably those at the Linus Pauling Institute, which lists a dozen principal investigators and faculty who study the role of micronutrients and phytochemicals in health and disease.

Items named after Pauling include "Pauling" street in Foothill Ranch, California, Linus Pauling Drive in Hercules, California, Linus and Eva Helen Pauling Hall at Soka University of America
Soka University of America
Soka University of America is a university located in Aliso Viejo, California, United States. It describes its mission as the fostering of a steady stream of global citizens committed to living a contributive life—with an emphasis on principles of pacifism, human rights, and the creative...

 in Aliso Viejo, California, Linus Pauling Middle School in Corvallis, Oregon
Corvallis, Oregon
Corvallis is a city located in central western Oregon, United States. It is the county seat of Benton County and the principal city of the Corvallis, Oregon Metropolitan Statistical Area, which encompasses all of Benton County. As of the 2010 United States Census, the population was 54,462....

, and Pauling Field
Condon State Airport
Condon State Airport , is a public airport located one mile northeast of the city of Condon in Gilliam County, Oregon, USA.The airport is also known as Pauling Field, after Nobel laureate Linus Pauling, who lived in Condon during his youth....

 a small airfield located in Condon, Oregon
Condon, Oregon
Condon is a city in Gilliam County, Oregon, United States. The population was 759 at the 2000 census. It is the county seat of Gilliam County. It is located on Oregon Route 19....

. Pauling spent his youth in Condon. Additionally, one wing of The Valley Library
The Valley Library
The Valley Library is the primary library of Oregon State University and is located at the school's main campus in Corvallis in the U.S. state of Oregon. Established in 1887, the school built its first library building in 1918, what is now Kidder Hall. The current building opened in 1963 as the...

 at Oregon State University bears his name. There is a psychedelic rock band in Houston, Texas, named The Linus Pauling Quartet
The Linus Pauling Quartet
The Linus Pauling Quartet is a psychedelic rock group which specializes in a specific subgenre known as "", but frequently dabbles also in Garage rock, Stoner rock, Punk rock, and Heavy Metal at various points throughout their discography. The LP4 was formed in 1994 by veterans of various local...

. Pauling Road in Monee, Illinois is another homage.

The Caltech Chemistry Department renamed room 22 of Gates Hall the Linus Pauling Lecture Hall, since Linus spent so much time there.

Linus Torvalds
Linus Torvalds
Linus Benedict Torvalds is a Finnish software engineer and hacker, best known for having initiated the development of the open source Linux kernel. He later became the chief architect of the Linux kernel, and now acts as the project's coordinator...

, developer of the Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...

 kernel, is named after Pauling.

On March 6, 2008, the United States Postal Service
United States Postal Service
The United States Postal Service is an independent agency of the United States government responsible for providing postal service in the United States...

 released a 41 cent stamp honoring Pauling. His description reads: "A remarkably versatile scientist, structural chemist Linus Pauling (1901-1994) won the 1954 Nobel Prize in Chemistry for determining the nature of the chemical bond linking atoms into molecules. His work in establishing the field of molecular biology; his studies of hemoglobin led to the classification of sickle cell anemia as a molecular disease." The other scientists on this sheet include Gerty Cori
Gerty Cori
Gerty Theresa Cori was an American biochemist who became the third woman—and first American woman—to win a Nobel Prize in science, and the first woman to be awarded the Nobel Prize in Physiology or Medicine.Cori was born in Prague...

, biochemist, Edwin Hubble
Edwin Hubble
Edwin Powell Hubble was an American astronomer who profoundly changed the understanding of the universe by confirming the existence of galaxies other than the Milky Way - our own galaxy...

, astronomer, and John Bardeen
John Bardeen
John Bardeen was an American physicist and electrical engineer, the only person to have won the Nobel Prize in Physics twice: first in 1956 with William Shockley and Walter Brattain for the invention of the transistor; and again in 1972 with Leon Neil Cooper and John Robert Schrieffer for a...

, physicist.

California Governor Arnold Schwarzenegger
Arnold Schwarzenegger
Arnold Alois Schwarzenegger is an Austrian-American former professional bodybuilder, actor, businessman, investor, and politician. Schwarzenegger served as the 38th Governor of California from 2003 until 2011....

 and First Lady Maria Shriver
Maria Shriver
Maria Owings Shriver is an American journalist and author of six best-selling books. She has received a Peabody Award, and was co-anchor for NBC's Emmy-winning coverage of the 1988 Summer Olympics. As executive producer of The Alzheimer's Project, Shriver earned two Emmy Awards and an Academy of...

 announced on May 28, 2008 that Pauling would be inducted into the California Hall of Fame
California Hall of Fame
Conceived by First Lady Maria Shriver, the California Hall of Fame was established at The California Museum for History, Women and the Arts to honor individuals and families who embody California’s innovative spirit and have made their mark on history...

, located at The California Museum for History, Women and the Arts
The California Museum for History, Women and the Arts
The California Museum, formerly The California Museum for History, Women and the Arts – home of the California Hall of Fame – is housed in the State Archives Building in Sacramento, one block from the State Capitol...

. The induction ceremony was scheduled to take place December 15, 2008. Pauling's son was asked to accept the honor in his place.

Pauling appears in the 2006 novel Visibility by Boris Starling
Boris Starling
Boris Starling is a British novelist and screenwriter. He was educated at Eton College and Trinity College, Cambridge, where he graduated with a first in History.-Life:Starling is the great-grandson of the English physiologist Ernest Starling...

, who later named his son Linus.

Honors and awards



Pauling received numerous awards and honors during his career. Following are awards and honors he has received.

Publications

  • Pauling, L. The Nature of the Chemical Bond. Cornell University Press ISBN 0-8014-0333-2
  • Pauling, L., and Wilson, E. B. Introduction to Quantum Mechanics with Applications to Chemistry (Dover Publications) ISBN 0-486-64871-0
  • Pauling, L. Vitamin C, the Common Cold and the Flu (W.H. Freeman and Company) ISBN 0-7167-0360-2
  • Cameron E. and Pauling, L. Cancer and Vitamin C: A Discussion of the Nature, Causes, Prevention, and Treatment of Cancer With Special Reference to the Value of Vitamin C (Camino Books) ISBN 0-940159-21-X
  • Pauling, L. How to Live Longer and Feel Better (Avon Books) ISBN 0-380-70289-4
  • Pauling, L. Linus Pauling On Peace - A Scientist Speaks Out on Humanism and World Survival (Rising Star Press) ISBN 0-933670-03-6
  • Pauling, L. General Chemistry (Dover Publications) ISBN 0-486-65622-5
  • A Lifelong Quest for Peace with Daisaku Ikeda
    Daisaku Ikeda
    is president of Sōka Gakkai International , a Nichiren Buddhist lay association which claims 12 million members in 192 countries and territories, and founder of several educational, cultural and peace research institutions.-Life and establishment of SGI:...

  • Pauling, L. The Architecture of Molecules
  • Pauling, L. No More War!
  • Abram Hoffer and Pauling, L. Healing Cancer. Complementary Vitamin & Drug Treatments (CCNM Press Inc.)

Further reading


External links