For a system of independent, distinguishable particles that have merely two quantum states with energies of 0 and epsilon and degeneracies of g0 and g1, it can be shown that the molar heat capacity of such a system is given by CV/n = R g1 (beta*epsilon)2 exp(-beta*epsilon) / [1+exp(-beta*epsilon)]2.
Compute this value for epsilon = 404, 881, and 3685 cm-1 the excitation energies of the 2P1/2 excited states of F, Cl, and Br, respectively at T = 300 K.