Abstract
State-specific multireference Moller-Plesset perturbation theory has been applied to the study of valence and Rydberg excitation energies of benzene. The results compare well with experiment. The calculated valence pi-pi* excitation energies (experimental values in parentheses) are ¹B_2u, 4.77 (4.90), ¹B_1u, 6.28 (6.20), ¹E_1u, 6.98 (6.94) and ¹E_2g, 7.88 (7.80) eV. Results of similar accuracy are obtained for the valence triplet excited states. The Rydberg excitation energies are also predicted with an accuracy of 0.18 eV or better.