Subpicosecond two-dimensional Raman spectroscopy applying broadband nanosecond laser radiation

We report first experimental and theoretical results applying non-transform-limited nanosecond laser pulses for realizing a fifth order Raman effect in nitrobenzene. Similar to femtosecond experiments this experiment enables to distinguish principally the action of rapid and slow modulation interactions on the molecular dynamics in liquids. A fast decay time of 120 fs and a slow decay time of approximately 1.5 ps are deduced from the experiments. They are assigned to nuclear motions and the dephasing time of the ν = 1345 cm−1 vibration of nitrobenzene, respectively.