Computational Insights into the CH3Cl+OH Chemical Reaction Dynamics at the Air–Water Interface

The reaction of methyl chloride with the hydroxyl radical OH is an important process in the troposphere. The kinetics of this reaction has been thoroughly studied in the gas phase, both experimentally and theoretically, but little is known about the effect of water on this reaction. In particular, investigating the reaction mechanism at the air–water interface is key in order to better understand the role of cloud water droplets and aerosols on the overall oxidation capacity of the troposphere. In this work, we have implemented a “rare event” approach combined to QM/MM (quantum mechanics and molecular mechanics) molecular dynamics simulations to investigate the dynamics of the H-abstraction reaction CH3Cl+OH→CH2Cl+H2O at the air–water interface. For comparison, high-level ab initio calculations for the reaction mechanism in the gas phase are also reported and accurate kinetic constants at different temperatures are provided. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, WeinheimThe authors are grateful to the French CNRS and the Spanish CSIC organizations for funding a collaborative PICS project (PIC2015FR1). M.M.C. and M.F.R.L. are grateful to the French CINES (project lct2550) for providing computational resources. J.M.A. thanks the Spanish Secretaria de Estado de Investigación, Desarrollo e Innovación (CTQ2014‐59768‐P) and the Generalitat de Catalunya (Grant 2014SGR139) for financial support, and the Consorci de Serveis Universitaris de Catalunya (CSUC) for providing computational resources.Peer reviewe