HIGH-FREQUENCY INTERACTION-INDUCED ROTOTRANSLATIONAL WINGS OF ISOTROPIC NITROGEN SPECTRA

The isotropic rototranslational scattering of nitrogen gas is studied in the frequency range 300-600 cm-1, both theoretically and experiment ally, at a density of 41 and 169 amagat. The isotropic double differen tial cross-section for scattered light is calculated theoretically con sidering first- and second-order dipole-induced dipole, first-order di pole-dipole-quadrupole, and dipole-induced octopole light scattering m echanisms as well as their cross contributions. The irreducible spheri cal form for the induced operator of these light scattering mechanisms was determined. Good comparison is found in the frequency range 300 4 50 cm-1 between the theoretical and experimental double differential c ross-sections. When an exponential contribution [exp(-nu/nu0)] with nu 0 = 118 cm-1 is considered to model very short-range light scattering mechanisms good comparison is found over the whole frequency range.