Depolarised Rayleigh scattering from liquid carbon monoxide,nitrogen and oxygen

The spectral distributions and scattering cross sections of depolarised Rayleigh scattering have been determined for liquid carbon monoxide, nitrogen and oxygen at 77 K and atmospheric pressure. It is shown that the scattering arises predominantly from molecular orientational fluctuations. The experimental scattering cross sections at 488 nm are 7 ± 1 for CO, 16 ± 1 for N₂ and 46 ± 4 for O₂ in units of 10^?30 cm² sr^?1 molecule^?1, based on a recently determined value for the absolute depolarised scattering intensity for liquid argon. The estimated proportions of induced anisotropy scattering are 10% for CO, 2.5% for N₂ and 0.8% for O₂. It is shown that there is appreciable free rotation of N₂ and CO in the liquids at this temperature but for O₂ this motion is dissipated much more efficiently by molecular interactions.