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: Q xx = −3.12, Q vy = 1.55, and Q zz = 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–C 2 H 4 and Ne–C 2 H 4 mixtures.