Ni. Butkovskaya et Dw. Setser, CHEMICAL-DYNAMICS OF THE OH AND OD RADICAL REACTIONS WITH H2S, CH3SCH3, AND CH3SH STUDIED BY INFRARED CHEMILUMINESCENCE, The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, 102(32), 1998, pp. 6395-6405
The infrared chemiluminescence of H2O and HOD molecules formed from th
e room-temperature reactions of OH and OD radicals with H2S, CH3SCH3,
and CH3SH was recorded by viewing a fast-flow reactor with a Fourier t
ransform spectrometer. Nascent vibrational distributions of the H2O an
d HDO product molecules were obtained by computer simulation of the in
frared spectra. According to our assignments for the nu 3 = 0 populati
ons, the vibrational distributions of HDO from the H2S and CH3SCH3 rea
ctions were inverted in the O-H stretching mode with a maximum in nu(3
) = 2 and nu(3) = 1, respectively, and the fraction of the available e
nergy released as vibrational energy is ([f nu],) approximate to 0.6 w
ith similar to 25-30% of the vibrational energy in the bending coordin
ate. The reaction with CH3SH gives a HOD vibrational distribution that
declines with increased nu(3); [f(nu)] is only approximate to 0.4, bu
t 40% of the vibrational energy is in the bending mode. For each react
ion, the vibrational distributions for H2O closely resemble those for
HOD, after allowance is made for the collision-induced equilibration b
etween the nu(1) and 2(nu 2) modes of H2O and the nu(1) and 2 nu(2) mo
des of HOD. The reduced vibrational energy disposal to H2O and HOD fro
m CH3SH is taken as evidence for a mechanism that differs from the dir
ect abstraction process for the H2S and CH3SCH3 reactions. These resul
ts are analyzed using information theory, and they also are compared w
ith the data from similar reactions of hydroxyl radicals and F atoms.
Secondary reactions of the sulfur-containing primary radicals (SH, CH3
S, and CH3SCH2) with NO2 and NO are discussed.