RESONANT RAMAN-SCATTERING IN O-2

Raman scattering of molecular oxygen in the region of the Schumann-Run ge absorption band system is calculated from first principles in the s econd order of perturbation theory in the interaction of photon-electr on operator. Quantitative predictions are given for the cross sections for scattering of photons and a detailed comparison is made with avai lable measurements. The behavior of Raman spectra near the predissocia ting rovibronic level (upsilon' = 5,N') in the B (3) Sigma(u)(-) elect ronic State of O-2 is investigated and shown to have significant depen dence on the detuning of the incident laser frequency. By casting the Raman transition matrix in a form similar to the Fano formalism, we ar e able to investigate the nature of the resonant and nonresonant scatt ering in the language of configuration interaction. By varying the pre dissociating width of the (upsilon' = 5,N') resonance, we make a compa rison with an earlier time-dependent wave-packet analysis. We also cal culate the depolarization ratio of the scattered photons parallel and perpendicular to the polarization of the incident laser beam for the d ifferent Raman branches for lines terminating in the v '' = 1 and v '' = 6 levels and comment on the relationship between resonant Raman sca ttering and fluorescence emission. (C) 1997 American Institute of Phys ics.