The influence of high-frequency modes on two pulse spectroscopy

Theoretical analyses of molecular response to ultrafast pulse excitation often do not account for the influence of high frequency modes on the spectrum of the molecule. In a previous article [M. N. Kobrak, E. M. Hiller, and S. A. Rice, J. Chem. Phys. 105, 9403 (1996)], we have shown that the high frequency modes of the molecule can dramatically change the distribution of an observable in processes initiated by a single ultrashort pulse. In this article we extend our treatment to allow for two-pulse processes, and apply the results to two models which have a qualitative resemblence to bacteriorhodopsin. (C) 1997 American Institute of Physics.