title: Theoretical and experimental investigations of rate coefficients of O(1D) + CH4at low temperature.
abstract: The rate coefficients of the barrierless O(1D) + CH4reaction are determined both theoretically and experimentally at 50-296 K. For the calculations, ring polymer molecular dynamics (RPMD) simulations are performed on the basis of a new neural network potential energy surface (PES) in the reactant asymptotic part. Only the reactant asymptotic part of the PES is constructed because of its barrierless and exothermic properties. Experimentally, the reaction rate coefficients are measured using a supersonic flow reactor. Pulsed laser photolysis of O3molecules is used as the source of O(1D) atoms, which are detected directly through vacuum ultraviolet laser induced fluorescence at 115 nm. The branching ratio for H atom production is measured by comparing the H atom yields of the O(1D) + CH4and O(1D) + H2reactions. At T ≥ 75 K, good agreement between theoretical and experimental rate coefficients is found, while at 50 K, the larger difference is discussed in detail.
authors.affiliation: Department of Applied Chemistry, Northwestern Polytechnical University, Youyi West Road 127, 710072 Xi'an, China. qingyong.meng@nwpu.edu.cn and State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, 116023 Dalian, China. zhangdh@dicp.ac.cn.
authors.forename: Qingyong
authors.initials: Q
authors.lastname: Meng
authors.affiliation: CNRS UMR 5255, Institut des Sciences Moléculaires, Université de Bordeaux, Bâtiment A12, 351 Cours de la Libération, F-33400 Talence, France. km.hickson@ism.u-bordeaux1.fr.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Hickson
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, 116023 Dalian, China. zhangdh@dicp.ac.cn.
authors.forename: Kejie
authors.initials: K
authors.lastname: Shao
authors.affiliation: CNRS UMR 5255, Institut des Sciences Moléculaires, Université de Bordeaux, Bâtiment A12, 351 Cours de la Libération, F-33400 Talence, France. km.hickson@ism.u-bordeaux1.fr.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Loison
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, 116023 Dalian, China. zhangdh@dicp.ac.cn.
authors.forename: Dong H
authors.initials: DH
authors.lastname: Zhang