title: An Experimental and Master Equation Study of the Kinetics of OH/OD + SO2: The Limiting High-Pressure Rate Coefficients.
abstract: The kinetics of the reaction OH/OD + SO2were studied using a laser flash photolysis/laser-induced fluorescence technique. Evidence for two-photon photolysis of SO2at 248 nm is presented and quantified, and which appears to have been evident to some extent in most previous photolysis studies, potentially leading to values for the rate coefficient k1that are too large. The kinetics of the reaction OH(v = 0) + SO2(T = 295 K, p = 25-300 torr) were measured under conditions where SO2photolysis was taken into account. These results, together with literature data, were modeled using a master equation analysis. This analysis highlighted problems with the literature data: the rate coefficients derived from flash photolysis data were generally too high and from the flow tube data too low. Our best estimate of the high-pressure limiting rate coefficient k1∞was obtained from selected data and gives a value of (7.8 ± 2.2) × 10-13cm3molecule-1s-1, which is lower than that recommended in the literature. A parametrized form of k1([N2],T) is provided. The OD(v = 0) + SO2(T = 295 K, p = 25-300 torr) data are reported for the first time, and master equation analysis reinforces our assignment of k1∞.
authors.forename: Mark A
authors.identifier: http://orcid.org/0000-0001-6710-4021
authors.initials: MA
authors.lastname: Blitz
authors.affiliation: Deloitte MCS , 3 Rivergate, Temple Quay, Bristol BR1 6GD, U.K.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Salter
authors.forename: Dwayne E
authors.initials: DE
authors.lastname: Heard
authors.forename: Paul W
authors.initials: PW
authors.lastname: Seakins