Ra. Brownsword et al., DYNAMICS OF THE H-PHASE REACTION, ABSOLUTE REACTIVE CROSS-SECTION FORCL(P-2(3(HCL GAS)2)) ATOM FORMATION/, Chemical physics letters, 289(3-4), 1998, pp. 241-246
The reaction of atomic hydrogen with HCl was studied in the gas phase
using the laser photolysis/vacuum-UV laser-induced fluorescence (LP/VU
V-LIF) 'pump-and-probe' technique. Translationally energetic H atoms w
ith an average energy of E-cm = 1.0 eV in the (H-HCl)-center-of-mass s
ystem were generated by laser photolysis of H2S at 248 nm. Doppler pro
files of nascent Cl(P-2(3/2)) atoms produced in the reactive collision
of the H atoms with room temperature HCl molecules were measured unde
r single collision conditions by VUV-LIF. For the H + HCl --> H-2 + Cl
(P-2(3/2)) reaction an absolute reaction cross-section sigma(R)(1.0 eV
) = (0.34 +/- 0.05) Angstrom(2) was determined by means of a photolyti
c calibration method using the 248 nm laser photolysis of PCl3 as refe
rence for well-defined concentrations of Cl atoms. Small amounts of Cl
in the (P-2(1/2)) excited state were observed in the H + HCl experime
nts. Bn upper limit of (0.02 +/- 0.01) Angstrom(2) was measured for th
e Cl(P-2(1/2)) formation cross-section in the H + HCl reaction at 1.0
eV. (C) 1998 Elsevier Science B.V. All rights reserved.