Dynamics of the gas–liquid interfacial reaction of O([sup 3]P) atoms with hydrocarbons.

Autor: Kelso, Hailey, Köhler, Sven P. K., Henderson, David A., McKendrick, Kenneth G.
Předmět:
Zdroj: Journal of Chemical Physics; 11/15/2003, Vol. 119 Issue 19, p9985-9988, 4p, 3 Graphs
Abstrakt: We describe an experimental approach to the determination of the nascent internal state distribution of gas-phase products of a gas–liquid interfacial reaction. The system chosen for study is O([sup 3]P) atoms with the surface of liquid deuterated squalane, a partially branched long-chain saturated hydrocarbon, C[sub 30]D[sub 62]. The nascent OD products are detected by laser-induced fluorescence. Both OD (v[sup ′]=0) and (v[sup ′]=1) were observed in significant yield. The rotational distributions in both vibrational levels are essentially the same, and are characteristic of a Boltzmann distribution at a temperature close to that of the liquid surface. This contrasts with the distributions in the corresponding homogeneous gas-phase reactions. We propose a preliminary interpretation in terms of a dominant trapping-desorption mechanism, in which the OD molecules are retained at the surface sufficiently long to cause rotational equilibration but not complete vibrational relaxation. The significant yield of vibrationally excited OD also suggests that the surface is not composed entirely of –CD[sub 3] endgroups, but that secondary and/or tertiary units along the backbone are exposed. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]
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