title: Vibrational excitation and product branching ratios in dissociation of the isotopologs of H3O: experiment and theory.
abstract: The dissociation dynamics of the Rydberg radical H3O and the deuterated isotopologs have been studied by dissociative charge exchange of H3O(+) with Cs. Center-of-mass kinetic energy release distributions were measured with a fast-beam translational spectrometer and compared with direct dynamics quasiclassical trajectory calculations with initial conditions from an ab initio potential energy surface for H3O(+). The experimental branching fractions for dissociation of each isotopolog were obtained and compared with the calculated branching fractions. The dominant dissociation channel for all species is elimination of an H/D atom, and the water product was formed with a significant vibrational inversion in stretching vibrations that varies with the mass of the leaving atom in the dissociation. Branching fractions for the mixed isotopologs show that H atom elimination is favored over D atom elimination. Given the importance of H3O(+) in plasmas, astrochemistry, and in condensed phases, the striking energy partitioning found in this neutralization process is notable.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0340, USA.
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Mann
authors.forename: Zhen
authors.initials: Z
authors.lastname: Xie
authors.forename: John D
authors.initials: JD
authors.lastname: Savee
authors.forename: Joel M
authors.initials: JM
authors.lastname: Bowman
authors.forename: Robert E
authors.initials: RE
authors.lastname: Continetti