Relaxation of excited normal modes in benzene

Abstract

Classical trajectories have been used to investigate energy relaxation of various excited C–C stretching, CCH bending, and CCC bending normal modes in benzene. These normal modes were initially excited up to about 10 000 cm−1. The calculated relaxation of the excited C–C ring breathing mode is in agreement with the recent experimental results of Chernoff, Myers, and Pruett [J. Chem. Phys. 85, 3732 (1986)]. In general, the relaxation of the excited normal modes involving C–C stretching, CCH bending, and CCC bending are at least several times slower than the relaxation of the CH stretch local mode. Mode-to-mode energy transfer was also investigated. Only those modes with frequencies close to that of the excited mode participate in the energy transfer.