A model Hamiltonian to simulate the complex photochemistry of benzene II.
The photophysics and photochemistry of benzene is a classic example of the richness of competing pathways available to a molecule after photoexcitation. Computer simulations are one way to provide a molecular picture for the dynamics behind the experimental observations. In this paper we develop a vibronic coupling Hamiltonian prepared in a previous paper [G. A. Worth, J. Photochem. Photobiol., A 190, 190 (2007)]. Using CASPT2 we add dynamic correlation to the description of the excited states, improving their accuracy dramatically. Seven coupled states and all vibrational modes are included in the model and the parameters are obtained by fitting to points provided by the quantum chemistry calculations. The model is shown to be a good fit of the adiabatic surfaces and its accuracy is demonstrated by the calculation of three absorption bands, which compare favorably with the experimentally obtained spectra.
Penfold
Thomas J
TJ
School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
Worth
Graham A
GA