Laser spectroscopic excitation function and reaction threshold studies of the H + DCI → HCI + D gas phase isotopic exchange reaction

Läuter, Almuth ; Vatsa, Rajesh K. ; Mittal, Jai P. ; Volpp, Hans-Robert ; Wolfrum, Jürgen (2006) Laser spectroscopic excitation function and reaction threshold studies of the H + DCI → HCI + D gas phase isotopic exchange reaction The Journal of Physical Chemistry A, 110 (9). pp. 3273-3279. ISSN 1089-5639

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Official URL: http://pubs.acs.org/doi/abs/10.1021/jp054818o

Related URL: http://dx.doi.org/10.1021/jp054818o

Abstract

The dynamics of the gas-phase hydrogen atom exchange reaction H + DCl → HCl + D were studied using the pulsed laser photolysis/laser induced fluorescence "pump-and-probe" method. Laser photolysis of H2S at 222 nm was used to generate nonequilibrium distributions of translationally excited hydrogen atoms at high dilution in a flowing moderator gas (Ar)/reagent (DCl) mixture. H and D atoms were detected with sub-Doppler resolution via Lyman-α laser induced fluorescence spectroscopy, which allowed the measurement of the line shapes of the moderated H atom Doppler profiles as well as the concentration of the D atoms produced in the H + DCl → HCl + D reaction. From the measured H atom Doppler profiles, the time evolution of the initially generated nascent nonequilibrium H atom speed distribution toward its room-temperature thermal equilibrium form was determined. In this way, the excitation function and the reaction threshold (E0 = 0.65 ± 0.13 eV) for the H + DCl → HCl + D reaction could be determined from the measured nonequilibrium D atom formation rates and single collision absolute reaction cross-section values of 0.12 ± 0.04 Å2 and 0.45 ± 0.11 Å2 measured at reagent collision energies of 1.0 and 1.4 eV, respectively.

Item Type:Article
Source:Copyright of this article belongs to American Chemical Society.
ID Code:84965
Deposited On:28 Feb 2012 11:59
Last Modified:28 Feb 2012 11:59

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