Semiclassical simulation of absorption spectra for a chromophore coupled to an anharmonic bath

The semiclassical (SC) initial value representation (IVR), combined with the generalized Filinov smoothing technique, is used to simulate the absorption spectrum for a model of a chromophore which is embedded in a dissipative environment. The environment is modeled by a bath of anharmonic (Morse) oscillators. The results of the study show that, depending on the specific parameters considered, the coupling to the dissipative environment may have a pronounced effect on the absorption spectrum of the chromophore. In particular, the influence of the size of the bath and the characteristic timescale of the environment is discussed. Furthermore, non-Condon effects, induced by the dependence of the transition-dipole moment on the reaction coordinate of the chromophore, are studied for selected examples. (C) 2004 Elsevier B.V. All rights reserved.