POLARIZABILITY EFFECTS IN RESONANT ULTRAFAST SPECTROSCOPY

We show that in resonant ultrafast spectroscopic experiments, such as in fluorescence interferometry, polarizability effects may be relevant . That is, due to the shortness of the light pulses in the molecular v ibrational time scales, Raman scattering processes are always present and therefore they should be included in the analysis of the correspon ding experimental situations. We present our arguments using an effect ive two-electronic-level Hamiltonian for a diatomic molecule that expl icitly includes molecular polarizability terms. We calculate fluoresce nce interferograms due to pairs of phase-locked ultrashort light pulse s in resonance with an electronic transition, and compare cases with a nd without polarizability terms. We also suggest how this analysis cou ld be used to measure electronic polarizabilities.