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Ionization
 
 
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Ionization is the physical
Physics

Physics is the natural science which examines basic concepts such as energy, force, and spacetime and all that derives from these, such as mass, charge, matter and its Motion ....
 process of converting an atom
Atom

|-! bgcolor=gray | Properties|-||}The atom is a basic unit of matter consisting of a dense, central atomic nucleus surrounded by a electron cloud of electric charge electrons....
 or molecule
Molecule

In chemistry, a molecule is defined as a sufficiently stable, electric charge neutral group of at least two atoms in a definite arrangement held together by very strong chemical bonds....
 into an ion
Ion

An ion is an atom or molecule which has lost or gained one or more electrons, giving it a positive or negative electrical charge. According to the Bohr_model this will be from or in the outer shield 'n'....
 by adding or removing charged particles such as electron
Electron

The electron is a subatomic particle that carries a negative electric charge. It has elementary particle and is believed to be a point particle....
s or other ions.

This process works slightly differently depending on whether an ion with a positive or a negative electric charge
Electric charge

Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. Electrically charged matter is influenced by, and produces, electromagnetic fields....
 is being produced. A positively charged ion is produced when an electron bonded to an atom (or molecule) absorbs enough energy to escape from the electric potential
Electric potential

At a point in space, the electric potential is the potential energy per unit of electric charge that is associated with a static electric field....
 barrier that originally confined it, thus breaking the bond and freeing it to move.






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Ionization is the physical
Physics

Physics is the natural science which examines basic concepts such as energy, force, and spacetime and all that derives from these, such as mass, charge, matter and its Motion ....
 process of converting an atom
Atom

|-! bgcolor=gray | Properties|-||}The atom is a basic unit of matter consisting of a dense, central atomic nucleus surrounded by a electron cloud of electric charge electrons....
 or molecule
Molecule

In chemistry, a molecule is defined as a sufficiently stable, electric charge neutral group of at least two atoms in a definite arrangement held together by very strong chemical bonds....
 into an ion
Ion

An ion is an atom or molecule which has lost or gained one or more electrons, giving it a positive or negative electrical charge. According to the Bohr_model this will be from or in the outer shield 'n'....
 by adding or removing charged particles such as electron
Electron

The electron is a subatomic particle that carries a negative electric charge. It has elementary particle and is believed to be a point particle....
s or other ions.

This process works slightly differently depending on whether an ion with a positive or a negative electric charge
Electric charge

Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interaction. Electrically charged matter is influenced by, and produces, electromagnetic fields....
 is being produced. A positively charged ion is produced when an electron bonded to an atom (or molecule) absorbs enough energy to escape from the electric potential
Electric potential

At a point in space, the electric potential is the potential energy per unit of electric charge that is associated with a static electric field....
 barrier that originally confined it, thus breaking the bond and freeing it to move. The amount of energy required is called the ionization potential
Ionization potential

The ionization potential, ionization energy or EI of an atom or molecule is the energy required to remove one mole of electrons from one mole of gaseous atoms or ions....
. A negatively charged ion is produced when a free electron collides with an atom and is subsequently caught inside the electric potential barrier, releasing any excess energy.

Ionization can generally be broken down into two types: sequential ionization and non-sequential ionization. In classical physics, only sequential ionization can take place and therefore refer to the Classical ionization section for more information. Non-sequential ionization violates several laws of classical physics and thus will be discussed in more detail in the Quantum ionization section.

Classical ionization


Applying only classical physics
Classical physics

Classical physics is a general term used to describe the branches of physics based on principles developed before the rise of general theory of relativity and Quantum mechanics, usually including special theory of relativity....
 and the Bohr model
Bohr model

In atomic physics, the Bohr model created by Niels Bohr depicts the atom as a small, positively charged atomic nucleus surrounded by electrons that travel in circular orbits around the nucleus—similar in structure to the solar system, but with electrostatic forces providing attraction, rather than gravity....
 of the atom makes both atomic and molecular ionization entirely deterministic, that is every problem will always have a definite and computable answer. According to classical physics it is absolutely necessary that the energy of the electron exceeds the energy difference of the potential barrier it is trying to pass. Conceptually this idea should make sense: the same way a person can not jump over a one meter wall without jumping at least one meter off the ground, an electron can not get over a 13.6 eV
Electronvolt

In physics, the electron volt is a unit of energy. By definition, it is equal to the amount of kinetic energy gained by a single unbound electron when it accelerates through an Electrostatics potential difference of one volt....
 potential barrier without at least 13.6 eV of energy.

Applying to positive ionization


According to these two principles, the energy required to release an electron is strictly greater than or equal to the potential difference between the current bound atomic or molecular orbital
Atomic orbital

An atomic orbital is a mathematical function that describes the wave-like behavior of an electron 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....
 and the highest possible orbital. If the energy absorbed exceeds this potential, then the electron is emitted as a free electron. Otherwise, the electron briefly enters an excited state
Excited state

Excitation is an elevation in energy level above an arbitrary baseline energy state. In physics there is a specific technical definition for energy level which is often associated with an atom being excited to an excited state....
 until the energy absorbed is radiated
Radiation

In physics, radiation describes any process in which energy emitted by one body travels through a medium or through space, ultimately to be absorbed by another body....
 out and the electron re-enters the lowest available state.

Applying to negative ionization


Due to the shape of the potential barrier, according to these principles a free electron must have an energy greater than or equal to that of the potential barrier in order to make it over. If it has enough energy to do so, it will be bound to the lowest available energy state, and the remaining energy will be radiated away. If the electron does not have enough energy to surpass the potential barrier, then it is forced away by the electrostatic force, described by Coulombs Law, associated with the electric potential barrier.

Sequential ionization


Sequential ionization is basically a description of how the ionization of an atom or molecule takes place. More specifically, it means that an ion with a +2 charge can only be created from an ion with a +1 charge or a +3 charge. That is, the numerical charge of an atom or molecule must change sequentially, always moving from one number to an adjacent, or sequential number.

Quantum ionization


In quantum mechanics
Quantum mechanics

Quantum mechanics is a set of principles underlying the most fundamental known description of all physical systems at the microscopic scale . Notable amongst these principles are both a dual wave-like and particle-like behavior of matter and radiation, and prediction of probabilities in situations where classical physics predicts certaintie...
 ionization can still happen classically where the electron has enough energy to make it over the potential barrier, but there is the additional possibility of tunnel ionization
Tunnel ionization

Tunnel ionization is a process in which electrons in an atom pass through the potential barrier and escape from the atom . In an intense electric field, the potential barrier of an atom is distorted drastically....
.

Tunnel ionization


Tunnel ionization
Tunnel ionization

Tunnel ionization is a process in which electrons in an atom pass through the potential barrier and escape from the atom . In an intense electric field, the potential barrier of an atom is distorted drastically....
 is ionization due to quantum tunneling. In classical ionization an electron must have enough energy to make it over the potential barrier, but quantum tunneling allows the electron simply to go through the potential barrier instead of going all the way over it because of the wave nature of the electron. The probability of an electron tunneling through the barrier drops off exponentially with the width of the potential barrier. Therefore, an electron with a higher energy can make it further up the potential barrier, leaving a much thinner barrier to tunnel through and thus a greater chance to do so.

Non-sequential ionization


When the fact that the electric field of light is an alternating electric field is combined with tunnel ionization, the phenomenon of non-sequential ionization emerges. An electron that tunnels out from an atom or molecule may be sent right back in by the alternating field, at which point it can either recombine with the atom or molecule and release any excess energy, or it also has the chance to further ionize the atom or molecule through high energy collisions. This additional ionization is referred to as non-sequential ionization for two reasons: one, there is no order to how the second electron is removed, and two, an atom or molecule with a +2 charge can be created straight from an atom or molecule with a neutral charge, so the integer charges are not sequential. Non-sequential ionization is often studied at lower laser-field intensities, since most ionization events are sequential when the ionization rate is high.

See also

  • Phase diagram
    Phase diagram

    A phase diagram in physical chemistry, mineralogy, and materials science is a type of Graph of a function used to show conditions at which thermodynamically-distinct phase can occur at thermodynamic equilibrium....
  • Phase transition
    Phase transition

    In thermodynamics, a phase transition is the transformation of a thermodynamic system from one phase to another.At phase-transition point, physical properties may undergo abrupt change- for instance, volume of the two phases may be vastly different....
  • Photoionization and Photoionization mode
    Photoionization mode

    A photoionization mode gives rise to a photoionization pattern, having very specific characteristics in terms of photoionization spatial distribution and density, as well as relative yields of photolytic species....
  • Quantum tunneling for detailed treatment of how tunneling works.
  • Thermal ionization
    Thermal ionization

    In thermal ionization, also referred to as surface ionization, chemically-purified material loaded onto a Electrical filament which is then heated to cause some of the material to be ionized as it boils off the hot filament....
  • Adiabatic ionization
    Adiabatic ionization

    Adiabatic ionization is a form of ionization in which an electron is removed from or added to an atom or molecule in its lowest energy state to form an ion in its lowest energy state....


Real Life Applications of Ions

  • Ions are a key element of ion thrusters which are a possible method to be used in powering space craft.
  • Trapped ion quantum computers are quantum computers which use suspended ions for data storage and calculations.
  • Detergent-free washer balls based on ionisation of oxygen molecules in the washing water
  • Drinking alkaline ionised water (from a water ioniser in your kitchen sink) is claimed to have several health benefits


Other uses of ions

  • An Ion Cannon
    Ion cannon

    In science fiction an ion cannon is a directed-energy weapon that fires beams of ions . Due to its power it is usually classified as a superweapon....
     is an idea currently in the realm of science fiction that would use beams of ionized atoms as a weapon. Classed as a particle beam weapon
    Particle beam weapon

    A particle beam weapon uses an ultra high energy beam of atoms or electrons to damage a material target by hitting it, and thus disrupting its atomic and molecular structure....
     and superweapon.
  • Bouncing radar signals off artificially ionized clouds to allow for mobile Over-the-horizon radar
    Over-the-horizon radar

    Over-the-horizon radar, or OTH , is a design concept for radar systems to allow them to detect targets at very long ranges, typically up to thousands of kilometers....
     and eliminate backscattering associated with the use of ionospheric reflection. This was explored by Defence Evaluation and Research Agency
    Defence Evaluation and Research Agency

    The Defence Evaluation and Research Agency was a part of the Ministry of Defence until July 2, 2001. At the time it was the United Kingdom's largest science and technology organisation....
     in the sixties and seventies.