Bond Lengths ] for the ground state and the first 4 excited electronic states. The calculations are done using the W1 and EOM-CCSD level of calculation for the ground state and excited electronic states, respectively. Figure demonstrates the comparison of non-dimensional C p as well as ∆H for the different cases discussed above. When considering only the ground state(dashed lines), as expected, the C p is lower since the effects of the higher electronic states are completely neglected when computing the partition function. The dotted lines correspond to case (ii) and the solid lines correspond to case (iii). Having level specific rotation and vibration frequencies lead to some differences in the specific heat however, these differences are not very large in the temperature range of our interest.