title: Photofragmentation translational spectroscopy of methyl azide (CH3N3) photolysis at 193 nm: molecular and radical channel product branching ratio.
abstract: We describe molecular-beam photofragment translational spectroscopy (PTS) experiments using electron impact (EI) ionization product detection to investigate the 193 nm photodissociation of methyl azide (CH(3)N(3)) under collision-free conditions. These experiments are used to derive the branching ratio between channels 1 and 2 [(1) radical channel: CH(3)N(3) + hν (λ = 193 nm) → CH(3) + N(3); (2) molecular channel: CH(3)N(3) + hν (λ = 193 nm) → CH(3)N + N(2)], which have been reported in a previous VUV-photoionization based PTS study. (1) Using electron impact ionization cross sections and ion fragmentation ratios for the various detected products, we derive the branching ratio (X(CH(3)-N(3)))/(X(CH(3)N-N(2))) = (0.017 ± 0.004)/(0.983 ± 0.004). Based on analysis of the kinetic energy release in the radical channel, we find that the cyclic form of N(3) is the dominant product in the radical channel. Only a small fraction of the radical channel produces ground state linear N(3).
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, USA. aquinto@chem.ucsb.edu
authors.forename: Alfredo
authors.initials: A
authors.lastname: Quinto-Hernandez
authors.forename: Jeremie
authors.initials: J
authors.lastname: Doehla
authors.forename: Wen-Tsung
authors.initials: WT
authors.lastname: Huang
authors.forename: Chien-Yu
authors.initials: CY
authors.lastname: Lien
authors.forename: Wei-Yen
authors.initials: WY
authors.lastname: Lin
authors.forename: Jim Jr-Min
authors.initials: JJ
authors.lastname: Lin
authors.forename: Alec M
authors.initials: AM
authors.lastname: Wodtke
mesh_terms: D001386:Azides / Q000737:chemistry*; D005609:Free Radicals / Q000737:chemistry; D010782:Photolysis; D013057:Spectrum Analysis
chemical_list: D001386:Azides; D005609:Free Radicals