Recombination and Reaction Dynamics Following Photodissociation of CH3OCl in Solution

• Published in: The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory Molecules, spectroscopy, kinetics, environment, & general theory, 2004-12, Vol.108 (50), p.10973-10979
• Main Authors: Elles, Christopher G, Cox, M. Jocelyn, Barnes, George L, Crim, F. Fleming
• Format: Article
• Language: English
• ISSN: 1089-5639; 1520-5215
• DOI: 10.1021/jp046627b

We observe the dynamics of the products following the photodissociation of methyl hypochlorite (CH3OCl) at 267 nm in solution. An ultraviolet charge-transfer transition reveals the evolution of Cl atoms in carbon tetrachloride, dichloromethane, 1,4-dichlorobutane, and chlorocyclohexane, and the data suggest that Cl atoms rapidly form a complex with the solvent. The Cl atom signal decays in 300 ps or less as a result of diffusive geminate recombination and bimolecular reaction. Diffusive geminate recombination consumes roughly 30% to 60% of the fragments that initially escape the solvent cage, while the remaining Cl atoms either react with excess CH3OCl or abstract a hydrogen atom from the solvent. Reaction with CH3OCl plays a significant role in carbon tetrachloride, dichloromethane, and 1,4-dichlorobutane, where the hydrogen abstraction reaction is relatively slow, but the faster decay of Cl atoms in chlorocyclohexane is a result of hydrogen abstraction from the solvent. A weak absorption due to the methoxy radical in cyclohexane, where we cannot probe the Cl atom directly, also shows evidence of diffusive geminate recombination and hydrogen abstraction from the solvent.