Manifestation of binary collisions in the Raman-allowed bending vibrational band of the S[formula omitted] molecule

Abstract

A careful, principally experimental Raman study which puts the focus on the ν5 bending vibrational band by gaseous room-temperature sulfur hexafluoride is reported. In essence, our results boil down in the following two findings. Firstly, the anisotropic Raman-allowed spectrum by that band, which for the first time was isolated from the recordings and calibrated on an absolute scale. Secondly, an absolute-calibrated binary collision-induced component, which was also for the first time extracted from the crude measurements in the wavenumber range 475–570 cm−1. Both spectra are depolarized and lead to parameters in agreement with the existing literature. The reported findings bring us one step closer to understanding how vibration mechanisms work in SF6 and show among other things that, at the ν5 frequency, collisions between molecules enhance light scattering by 0.8% at 1 atm and by 13% at 15 atm of sulfur hexafluoride gas pressure.