derive an expression for the contribution of:

Apr 2013
Derive an expression for the contribution to the molar heat capacity at constant volume CV,m(T) of Cl atoms from these electronic states and evaluate it for T = 500 K.

THEORY: The electronic ground state of the Cl atom is fourfold degenerate, while the first electronically excited state is doubly degenerate and lies 881 cm–1 above the ground state.

here is my work so far:

now I know that I have to also sub in this somewhere but I want to mak the expression simpler: