Collision-induced absorption in the far infrared region in ethylene – rare gas mixtures

Abstract

The collision-induced spectra of mixtures of ethylene and each of the rare gases He, Ne, Ar, Kr, and Xe in the 40–360 cm−1 region has been obtained using a Michelson Fourier transform spectrometer. In addition, improved results for the collision-induced spectrum of pure ethylene gas are reported using this spectrometer as well as a far infrared laser source. All the results from the pure gas and gas mixtures have been analyzed according to the theory for quadrupolar-induced translation–rotational absorption. From this analysis the following values for the components of the quadrupolar tensor are: Qxx = −3.12, Qvy = 1.55, and Qzz = 1.57 B, which are somewhat lower estimates (in absolute value) than previously reported by us. Evidence for induction by other mechanisms (other than quadrupolar) has been obtained for the He–C2H4 and Ne–C2H4 mixtures.