title: Conical-intersection quantum dynamics of OH(A2Σ+) + H(2S) collisions.
abstract: We present the conical-intersection quantum dynamics of the nonreactive quenching (NQ) OH(A(2)Σ(+)) + H'((2)S) → OH(X(2)Π) + H'((2)S), exchange (X) OH(A(2)Σ(+)) + H'((2)S) → OH'(A(2)Σ(+)) + H((2)S), exchange-quenching (XQ) OH(A(2)Σ(+)) + H'((2)S) → OH'(X(2)Π) + H((2)S), and reaction (R) OH(A(2)Σ(+)) + H'((2)S) → O((1)D) + H2(X(1)Σg (+)) collisions. We obtain initial-state-resolved reaction probabilities, cross sections, and rate constants by considering OH in the ground vibrational state and in the rotational levels j0 = 0, 1, 2, and 5. Coupled-channel real wavepackets (WPs) on the X̃(1)A(') and B̃(1)A(') coupled electronic states are propagated by using the Dobbyn and Knowles diabatic potential surfaces and coupling [A. J. Dobbyn and P. J. Knowles, Mol. Phys. 91, 1107 (1997) and A. J. Dobbyn and P. J. Knowles, Faraday Discuss. 110, 207 (1998)], and performing asymptotic or flux analysis. NQ is the preferred product channel, followed by XQ, R, and X. Moreover, the nonadiabatic quenching processes account for more than 80% of the total rate constants. WP snapshots show a reaction mechanism in good agreement with reaction probabilities. NQ, XQ, and R cross sections, and NQ rate constants decrease with the collision energy and j0, whereas the X reactivity increases, and XQ and R rates are nearly constant with j0. In general, quantum rate constants are smaller than experimental or quasiclassical data.
authors.affiliation: Departament de Química Física i Institut de Química Teòrica i Computacional, Universitat de Barcelona, C∕ Martí i Franquès 1, 08028 Barcelona, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Gamallo
authors.forename: Sinan
authors.initials: S
authors.lastname: Akpinar
authors.forename: Paolo
authors.initials: P
authors.lastname: Defazio
authors.forename: Carlo
authors.initials: C
authors.lastname: Petrongolo
mesh_terms: D006859:Hydrogen / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D017665:Hydroxyl Radical; D006859:Hydrogen