Non-Markovian energy-corrected sudden model for the rototranslational spectrum of N-2

A model generalizing the isotropic-scattering-energy-corrected sudden (ECS) relaxation matrix to arbitrary rank spectra is developed on the basis of a theoretical expression proposed by A.P. Kouzov [Spectral Line Shapes, 14th International Conference on Spectral Line Shapes, State College, PA, 1998, edited by R. M. Herman, AIP Conf. No. 467 (AIP, Woodbury, NY, 1999), Vol. 10, p. 497] for the case of non-Markovian collisions. The constructed matri x obeys all known general relations obtained from first principles: both ma trix and Ben-Reuven [Phys. Rev. 141, 34 (1966)] symmetries as well as the d ouble-sided sum rules, In the framework of the present formalism the usual ad hoc detailed balance factor is replaced by a more physical one. Without any additional parameter with respect to the Markovian ECS, this model give s a reasonable description of the N-2 anisotropic depolarized spectrum in t he whole frequency range up to the far wing. [S1050-2947(99)08507-8].