title: Product branching between reactive and nonreactive pathways in the collisional quenching of OH A 2Sigma+ radicals by H2.
abstract: The collisional quenching of OH radicals in their excited A 2Sigma+ electronic state by molecular hydrogen is examined to determine the partitioning between reactive and nonreactive pathways. This is achieved using a pump-probe laser technique to compare the population prepared in the excited OH A 2Sigma+ state with that produced in the OH X 2Pi ground state from nonreactive quenching. Only a small fraction of the products, less than 15%, arise from nonreactive quenching; reactive quenching is the dominant product channel. The branching between the product channels provides a new dynamical signature of the conical intersection region(s) that couple the excited state potential for OH A 2Sigma++H2 with OH X 2Pi+H2 and H2O+H products.
authors.affiliation: Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA.
authors.forename: Logan P
authors.initials: LP
authors.lastname: Dempsey
authors.forename: Craig
authors.initials: C
authors.lastname: Murray
authors.forename: Marsha I
authors.initials: MI
authors.lastname: Lester