title: Isotopic and quantum-rovibrational-state effects for the ion-molecule reaction in the collision energy range of 0.03-10.00 eV.
abstract: We report detailed quantum-rovibrational-state-selected integral cross sections for the formation of H3O+via H-transfer (σHT) and H2DO+via D-transfer (σDT) from the reaction in the center-of-mass collision energy (Ecm) range of 0.03-10.00 eV, where (vvv) = (000), (100), and (020) and . The Ecminhibition and rotational enhancement observed for these reactions at Ecm< 0.5 eV are generally consistent with those reported previously for H2O++ H2(D2) reactions. However, in contrast to the vibrational inhibition observed for the latter reactions at low Ecm< 0.5 eV, both the σHTand σDTfor the H2O++ HD reaction are found to be enhanced by (100) vibrational excitation, which is not predicted by the current state-of-the-art theoretical dynamics calculations. Furthermore, the (100) vibrational enhancement for the H2O++ HD reaction is observed in the full Ecmrange of 0.03-10.00 eV. The fact that vibrational enhancement is only observed for the reaction of H2O++ HD, and not for H2O++ H2(D2) reactions suggests that the asymmetry of HD may play a role in the reaction dynamics. In addition to the strong isotopic effect favoring the σHTchannel of the H2O++ HD reaction at low Ecm< 0.5 eV, competition between the σHTand σDTof the H2O++ HD reaction is also observed at Ecm= 0.3-10.0 eV. The present state-selected study of the H2O++ HD reaction, along with the previous studies of the H2O++ H2(D2) reactions, clearly shows that the chemical reactivity of H2O+toward H2(HD, D2) depends not only on Ecm, but also on the rotational and vibrational states of H2O+(X2B1). The detailed σHTand σDTvalues obtained here with single rovibrational-state selections of the reactant H2O+are expected to be valuable benchmarks for state-of-the-art theoretical calculations on the chemical dynamics of the title reaction.
authors.affiliation: Department of Chemistry, University of California, Davis, Davis, CA 95616, USA. cyng@ucdavis.edu.
authors.forename: Yuntao
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Department of Chemistry, University of California, Davis, Davis, CA 95616, USA. cyng@ucdavis.edu.
authors.forename: Bo
authors.initials: B
authors.lastname: Xiong
authors.affiliation: Department of Chemistry, University of California, Davis, Davis, CA 95616, USA. cyng@ucdavis.edu.
authors.forename: Yih Chung
authors.identifier: http://orcid.org/0000-0002-3763-1864
authors.initials: YC
authors.lastname: Chang
authors.affiliation: Department of Chemistry, University of California, Davis, Davis, CA 95616, USA. cyng@ucdavis.edu.
authors.forename: C Y
authors.identifier: http://orcid.org/0000-0003-4425-5307
authors.initials: CY
authors.lastname: Ng