Collisional deactivation of vibrationally hot vinyl chloride by He, Ar, N 2 and Co 2

Abstract

Energy transfer from vibrationally excited vinyl chloride (VC *), produced in the photolysis of 3-chloro-3-methyldiazirine was studied measuring the yields φ of VC * unimolecular decomposition at several pressures using N 2, Ar, He and CO 2 as buffer gases. The previously reported initial energy distributions, f( E), allowed the determination of the average energy transferred by collision, <Δ E > , but, as the f( E) are not precisely known, only upper limits of the <Δ E > will be given. The values of <Δ E > determined from the 365 nm photolysis data are (in kcal mol −1): 0.25 (He), 0.6 (Ar), 0.6 (N 2) and 0.75 (CO 2). Results from 337 nm photolysis with He are much higher, revealing both the use of an inadequate f( E) and an increase in <Δ E > with energy of VC *. Comparisons with other experimental studies and with energy transfer theories have been made.