Manifestation of binary collisions in the Raman-allowed bending vibrational band of the SF6 molecule

Abstract

A careful, principally experimental Raman study which puts the focus on the ${\nu }_5$ 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 S$F_6$ and show among other things that, at the ${\nu }_5$ frequency, collisions between molecules enhance light scattering by 0.8% at 1 atm and by 13% at 15 atm of sulfur hexafluoride gas pressure.