VIBRATIONAL COHERENCE AND RELAXATION DYNAMICS IN THE PRIMARY DONOR STATE OF THE MUTANT REACTION-CENTER OF RHODOBACTER-CAPSULATUS - THEORETICAL-ANALYSIS OF PUMP-PROBE STIMULATED-EMISSION

The effects of vibrational coherence and vibrational relaxation on the pump-probe stimulated emission are theoretically studied on the basis of the perturbative density operator method and the transient linear susceptibility theory. The time-resolved profiles are simulated for th e system with the single vibrational mode at the several temperature a t the several probing frequencies. The quantum beats appeared in the p rofiles are shown to rapidly dephase as the temperature increases. The calculations imply that the time constant of the vibrational relaxati on of the intra-dimer mode in the special pair of the D-LL mutant of R hodobacter capsulatus is approximately the order of 300 femtosecond at the low temperatures.