title: Ring-polymer molecular dynamics studies on the rate coefficient of the abstraction channel of hydrogen plus ethane, propane, and dimethyl ether.
abstract: To accurately compute the rates of the abstraction channels of hydrogen plus ethane (Et), propane (Pr), and dimethyl ether (DME), ring-polymer molecular dynamics (RPMD) method is used in conjunction with the recently constructed local permutation invariant polynomial neural-networks potential energy surface of the parent H + CH4system [Q. Meng et al., J. Chem. Phys. 144, 154312 (2016)]. For H + Et, one of the H atoms in CH4of the parent system is replaced by a methyl group, while for the H + DME reaction, it is replaced by the methoxyl group. For the H + Pr reaction, replacing one of the H atoms in CH4by an ethyl group, the terminal channel is built, meanwhile the middle channel is considered through replacing two H atoms in CH4by two methyl groups. Since the potential energy barriers of the title reactions must differ from the H + CH4barrier, the corrections have to be made by computing the ratio of free-energy barriers between H + CH4and the title reactions at coupled cluster with a full treatment singles and doubles (where the triples contribution is calculated by perturbation theory, that is, CCSD(T)) level. Comparing the present RPMD rates with the previous theoretical and experimental results, good agreement can be found. Moreover, probable reasons for the deviation between the present RPMD rates and the previous experimental ones are discussed.
authors.affiliation: Department of Applied Chemistry, Northwestern Polytechnical University, Youyi West Road 127, 710072 Xi'an, China.
authors.forename: Qingyong
authors.initials: Q
authors.lastname: Meng
authors.affiliation: State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, 116023 Dalian, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Chen