title: Photodissociation dynamics of formyl fluoride (HFCO) at 193 nm: branching ratios and distributions of kinetic energy.
abstract: Following photodissociation of formyl fluoride (HFCO) at 193 nm, we detected products with fragmentation translational spectroscopy utilizing a tunable vacuum ultraviolet beam from a synchrotron for ionization. Among three primary dissociation channels observed in this work, the F-elimination channel HFCO-->HCO+F dominates, with a branching ratio approximately 0.66 and an average release of kinetic energy approximately 55 kJ mol(-1); about 17% of HCO further decomposes to H+CO. The H-elimination channel HFCO-->FCO+H has a branching ratio approximately 0.28 and an average release of kinetic energy approximately 99 kJ mol(-1); about 21% of FCO further decomposes to F+CO. The F-elimination channel likely proceeds via the S1 surface whereas the H-elimination channel proceeds via the T1 surface; both channels exhibit moderate barriers for dissociation. The molecular HF-elimination channel HFCO-->HF+CO, correlating with the ground electronic surface, has a branching ratio of only approximately 0.06; the average translational release of 93 kJ mol(-1), approximately 15% of available energy, implies that the fragments are highly internally excited. Detailed mechanisms of photodissociation are discussed.
authors.affiliation: National Synchrotron Radiation Research Center (NSRRC), 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan. shlee@nsrrc.org.tw
authors.forename: Shih-Huang
authors.initials: SH
authors.lastname: Lee
authors.forename: Chia-Yan
authors.initials: CY
authors.lastname: Wu
authors.forename: Sheng-Kai
authors.initials: SK
authors.lastname: Yang
authors.forename: Yuan-Pern
authors.initials: YP
authors.lastname: Lee