Vibrational heat capacity of the molecule

Definition:

n_j - frequencies of normal vibrations in the molecule

h - Planck's constant

k - Boltzmann's constant

T - absolute temperature (K)

References:

1. D.A. McQuarrie, Statistical Thermodynamics, Harper & Row Publishers, New York, 1973.

2. A.I. Akhiezer, S.V. Peltminskii, Methods of Statistical Physics, Pergamon  Press,  Oxford, 1981.