Coherent two-dimensional Raman scattering: Frequency-domain measurement of the intra- and intermolecular vibrational interactions

A new experiment of frequency-domain coherent two-dimensional Raman scattering is theoretically proposed. By using three fields whose wave vectors and frequencies are independently controlled, one can measure the nonlinear Raman responses in either gas or condensed phases. The connection to the time-domain femtosecond two-dimensional Raman spectroscopy is completely established. By considering several limiting cases in detail, it is found that from the coherent 2D Raman scattering spectrum one can obtain quantitative information on the anharmonicity, anharmonic mode coupling, and polarizability coupling.