Equipartition of Energy Equipartition of Energy Number of Degrees of Freedom- total number of ways of absorbing energy. Equal to 3 N where N is the number of atoms in the molecule. For two atoms you would have x,y,z for each atom. Nuclear Motions of Polyatomic molecules. Either 2 or 3 depending on whether the molecule is linear or non linear.
Vibration has both a potential and a kinetic energy component.
Because of this each will contribute R to C v at high temperatures, but because the vibrations are excited only at temperatures much greater than room temperature the usual assumption is that the contribute 0. Only vibrations are present. Metallic vibrations are fully excited at room temperature and ionic solids are not.