Journal of Chemical Physics, Vol.105, No.16, 6596-6606, 1996
Dephasing of a Solvated 2-Level System - A Semiclassical Approach for Parallel Computing
The statically broadened vibronic line shape of a molecular solute in a liquid solution may be computed from a knowledge of the equilibrium structure of the fluid. By contrast, calculation of the contribution of solvent nuclear motions to this lineshape requires the use of semiclassical mechanics. Liquid-state electronic spectra have previously been calculated with a semiclassical approach relating the Line shape to fluctuations in the electronic energy gap as the fluid evolves classically on the ground-state potential surface. We propose an alternative formulation that incorporates dynamics on both the ground-state and excited-state surfaces. While more computationally intensive, this approach lends itself readily to parallel computation. Line shapes using both methods are computed for a Lennard-Jones solute in a Lennard-Jones solvent, for which the depth of the potential well characterizing solute-solvent interactions changes with electronic state.
Keywords:PHOTON-ECHOES;ELECTRONIC-SPECTRA;MOLECULAR-DYNAMICS;POLAR FLUIDS;CHROMOPHORES;TRANSITION;RELAXATION;FORMALISM;GLASSES;DENSITY