Rotational partition function
Encyclopedia
Rotational energies
Rotational energy
The rotational energy or angular kinetic energy is the kinetic energy due to the rotation of an object and is part of its total kinetic energy...

 are quantized. For a diatomic molecule like CO or HCl, the allowed rotational energies are
The number of degenerate states
Degenerate energy level
In physics, two or more different quantum states are said to be degenerate if they are all at the same energy level. Statistically this means that they are all equally probable of being filled, and in Quantum Mechanics it is represented mathematically by the Hamiltonian for the system having more...

g_j for each level j is 2j+1. The rotational partition function is therefore
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK