Non-Markovian far-wing rotational Raman spectrum from translational modeling - art. no. 012715

An improved version of the recently developed non-Markovian energy correcte d sudden (ECS) model [J. V. Buldyreva and L. Bonamy, Phys. Rev. A 60, 370 ( 1999)] is proposed to ensure good accuracy of the quasiexponential behavior of the scattered light intensity vs frequency that is observed experimenta lly in the far wings of nitrogen spectra. To this end, the more refined tra nslational spectrum proposed by Birnbaum and Cohen [Can. J. Phys. 54, 593 ( 1976)] is used as the adiabaticity factor. At low frequencies it reduces to the traditional one-parameter Lorentzian shape which describes the long-ti me translational dynamics and allows the basic ECS transition rates to be i dentified. At high frequencies it introduces an additional parameter which describes the short-time dynamics. The value of this parameter at room temp erature and at low temperature (150 K) is obtained by fitting the far-wing theoretical intensities of the depolarized nitrogen spectra to their experi mental values. This value compares favorably with its theoretical evaluatio n.