Solvation Stokes-Shift Dynamics Studied by Chirped Femtosecond Laser Pulses.
The early optical dynamic response, resulting population, and electronic coherence are investigated experimentally and modeled theoretically for IR144 in solution. The fluorescence and stimulated emission response are studied systematically as a function of chirp. The magnitude of the chirp effect on fluorescence and stimulated emission is found to depend quadratically on pulse energy, even where excitation probabilities range from 0.02 to 5%, in the so-called "linear excitation regime". Interestingly, the shape of the chirp dependence on fluorescence and stimulated emission is found to be independent of pulse energy. The chirp dependence reveals dynamics related to solvent rearrangement following excitation and also depends on electronic relaxation of the chromophore. The experimental results are successfully simulated using a four-level model in the presence of inhomogeneous broadening of the electronic transitions.
†Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States.
Arkaprabha
A
Konar
†Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States.
Vadim V
VV
Lozovoy
†Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, United States.|‡Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, United States.
Marcos
M
Dantus
coherent control; decoherence; pulse shaping; relaxation