Simple force field models for excited-state vibrations of benzene and polycyclic aromatic hydrocarbons (PAH) have been established. Root-mean-square frequency errors by the present MO/8DeltaE and MO/8DeltaPi methods were found to be comparable with or even better than the conventional CCSD(T) and CIS calculations. The very strong vibronic coupling of the vs mode for the S-2(B-1(1a)) and T-1 (B-3(1u)) states of benzene proposed in jet-spectroscopic studies by Hiraya and Shobatake and in EELS studies by Swiderek et al. has given confirmation by the present calculations. The present methods hold promise for predicting excited-state vibrations for PAH in the accuracy of 40 cm(-1). (C) 2002 Published by Elsevier Science B.V.