Time-Resolved Spectroscopy of Vibrational Overtones and Two-Phonon States

The authors propose the application of time-resolved nonlinear optical techniques to the selective study of the dynamics of vibrational overtones and two-phonon states in condensed media. They present the first experimental demonstration of picosecond coherent anti-Stokes higher-order Raman scattering on the first overtone and the bound two-phonon state of the ${\nu }_2$ mode in liquid and crystalline C${\mathrm{S}}_2$, respectively, and describe its dynamics and deexcitation channel in terms of a simple effective Hamiltonian.