Nonlinear Response Function for Ultrafast Pump-probe Polarization Spectroscopy

A unified nonlinear response function for pump-probe polarization spectroscopy is developed. The response function is expressed in time-domain and frequency-domain and is evaluated with Liouville space operator. These are applied to femtosecond Raman-induced polarization spectroscopy of rotational coherence in ground and excited electronic state,in which the superposition of the pulses is considered. The diagrammatic representation of the third order polarization is also given.