HO + NO: Kinetics, Thermochemistry, and Evidence for a Bimolecular Product Channel.

A master equation (ME) analysis of available experimental data has been carried out on the reaction HO + NO + M ⇋ HONO + M (1a)/(-1a). The analysis, based on the ME code MESMER, uses both the association and dissociation kinetic data from the literature, and provides improved thermochemistry on reaction 1a. Our preferred model assigns two low-frequency vibrations of HONO as hindered rotors and couples these to the external rotations.

Temperature and Pressure Studies of the Reactions of CH3O2, HO2, and 1,2-C4H9O2 with NO2.

A novel technique has been developed for the detection of peroxy radicals in order to study their kinetics with NO2. Peroxy radicals (RO2, where R = H, CH3, and 1,2-C4H9) were produced by laser flash photolysis and were probed by photodissociation of the RO2 and the subsequent detection of either OH or CH3O photofragments by laser-induced fluorescence. Reaction 1 , CH3O2 + NO2 + M ⇌ CH3O2NO2 + M (M = N2), was studied between 25 and 400 Torr at 295 K, giving results in excellent agreement with the literature.

Experimental and master equation study of the kinetics of OH + C2H2: temperature dependence of the limiting high pressure and pressure dependent rate coefficients.

The kinetics of the reaction OH + C2H2 have been studied using laser flash photolysis at 248 nm to generate OH radicals and laser-induced fluorescence to monitor OH removal. An attempt was made to use the rate coefficients OH (v = 1,2) + C2H2 to determine the limiting high-pressure rate coefficient, k(1a)(infinity), over the temperature range of 195-823 K. This method is usually applicable if the reaction samples the potential energy well of the adduct, HOC2H2, and if intramolecular vibrational relaxation is fast.