SEPARATION OF NUCLEAR AND ELECTRONIC CONTRIBUTIONS TO FEMTOSECOND 4-WAVE-MIXING DATA

A Fourier-transform method that separates the nuclear and non-resonant electronic contributions to the nonlinear-optical transient detected for transparent materials is developed and applied to femtosecond optical heterodyne detected optical Kerr effect data fluorobenzene and iodobenzene liquids. This method generates directly the impulse response function for nuclear motion, as well as the nuclear contribution to the measured transients. The role of rapidly dephased, intermolecular vibrational motions in shaping the detected response is explicitly revealed in a frequency-domain representation of the temporal data.