title: Crossed-beam radical-radical reaction dynamics of O(3P)+C3H3-->H(2S)+C3H2O.
abstract: The radical-radical oxidation reaction, O(3P)+C3H3 (propargyl)-->H(2S)+C3H2O (propynal), was investigated using vacuum-ultraviolet laser-induced fluorescence spectroscopy in a crossed-beam configuration, together with ab initio and statistical calculations. The barrierless addition of O(3P) to C3H3 is calculated to form energy-rich addition complexes on the lowest doublet potential energy surface, which subsequently undergo direct decomposition steps leading to the major reaction products, H+C3H(2)O (propynal). According to the nascent H-atom Doppler-profile analysis, the average translational energy of the products and the fraction of the average transitional energy to the total available energy were determined to be 5.09+/-0.36 kcal/mol and 0.077, respectively. On the basis of a comparison with statistical prior calculations, the reaction mechanism and the significant internal excitation of the polyatomic propynal product can be rationalized in terms of the formation of highly activated, short-lived addition-complex intermediates and the adiabaticity of the excess available energy along the reaction coordinate.
authors.affiliation: Department of Chemistry and Center for Electro- and Photo-Responsive Molecules, Korea University, 1, Anam-dong, Seoul 136-701, Korea.
authors.forename: Lee-Kyoung
authors.initials: LK
authors.lastname: Kwon
authors.forename: Mi-Ja
authors.initials: MJ
authors.lastname: Nam
authors.forename: Sung-Eui
authors.initials: SE
authors.lastname: Youn
authors.forename: Sun-Kyu
authors.initials: SK
authors.lastname: Joo
authors.forename: Hohjai
authors.initials: H
authors.lastname: Lee
authors.forename: Jong-Ho
authors.initials: JH
authors.lastname: Choi