Theoretical Analysis of Ultrafast Fluorescence Depletion of Vibrational Relaxation of Dye Molecules in Solution

Abstract

Ultrafast vibrational relaxation and solvation dynamics of electronically excited dye molecules in solution are theoretically studied on the basis of the perturbative density operator method and the transient linear susceptibility theory. Femtosecond time-resolved profile of the stimulated emission pumping fluorescence depletion (SEP FD) is simulated with a single vibrational mode. The results show that the fast and the slow SEP components reflect primarily the vibrational relaxation and the solvation effect, respectively, in the first excited state S1 of the dye molecules.