Short-time solvation dynamics probed by phase-locked heterodyne detected pump-probe

Phase-locked heterodyne detected pump-probe experiments are reported on solutions of a dye molecule in ethylene glycol, methanol and acetonitrile. By performing experiments at different phase-lock wavelengths, the real and imaginary parts of the line broadening function g(t) could be mapped out. The imaginary part of g(t) is directly related to dissipative dynamics. Comparison of the experimental data with calculations based on the Brownian oscillator model yields solvation frequencies that are substantial higher than those reported using MD simulations on similar systems.