Multireference Mّller-Plesset perturbation treatment for valence and Rydberg excited states of benzene

State-specific multireference Møller-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 π-π∗ excitation energies (experimental values in parentheses) are 1B2u, 4.77 (4.90), 1B1u, 6.98 (6.20), 1E1u, 6.98 (6.94) and 1E2g, 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.