Electronic quenching of OH A²Σ⁺ radicals in single collision events with H₂ and D₂: a comprehensive quantum state distribution of the OH X²Π products

Dempsey, L.P., Murray, C., Cleary, P.A. and Lester, M.I. (2008) Electronic quenching of OH A²Σ⁺ radicals in single collision events with H₂ and D₂: a comprehensive quantum state distribution of the OH X²Π products. Physical Chemistry Chemical Physics, 10(10), p. 1424. (doi: 10.1039/b715611a)

Abstract

A pump–probe laser-induced fluorescence technique has been used to examine the nascent OH X ²Π product state distribution arising from non-reactive quenching of electronically excited OH A ²Σ⁺ by molecular hydrogen and deuterium under single-collision conditions. The OH X ²Π products were detected in v″ = 0, 1 and 2; the distribution peaks in v″ = 0 and decreases monotonically with increasing vibrational excitation. In all vibrational levels probed, the OH X ²Π products are found to be highly rotationally excited, the distribution peaking at N″ = 15 when H₂ was used as the collision partner and N″ = 17 for D₂. A marked propensity for production of Π(A′) Λ-doublet levels was observed, while both OH X ²Π spin–orbit manifolds were equally populated. These observations are interpreted as dynamical signatures of the nonadiabatic passage of the OH + H₂/D₂ system through the seams of conical intersection that couple the excited state (2 ²A′) and ground state (1 ²A′) surfaces.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Murray, Dr Craig
• Authors: Dempsey, L.P., Murray, C., Cleary, P.A., and Lester, M.I.
• Subjects: Q Science > QD Chemistry
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Physical Chemistry Chemical Physics
• Journal Abbr.: Phys. Chem. Chem. Phys.
• ISSN: 1463-9076
• ISSN (Online): 1463-9084
• Published Online: 30 November 2007