Ra. Brownsword et al., EXCITATION-FUNCTION AND REACTION THRESHOLD STUDIES OF ISOTOPE-EXCHANGE REACTIONS - H-2-]D+HD AND H+D2O-]D+HOD(D), The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, 101(36), 1997, pp. 6448-6454
Laser photolysis of H2S at 248 nm and at 193 nm was used to generate n
onequilibrium distributions of translationally energetic hydrogen atom
s at high dilution in a flowing moderator gas (N-2 or Ar). The pulsed
laser photolysis/laser-induced fluorescence ''pump-and-probe'' method
allowed the measurement of the line shapes of the moderated H atom Dop
pler profiles as well as the concentrations of D atoms produced in the
reactive collisions between the H atoms and Dr or D2O reagents. H and
D atoms were detected with sub-Doppler resolution via (2p(2)P <-- 1s(
2)S) laser-induced fluorescence. The measured H atom Doppler profiles
were used to describe the evolution of the initially generated nascent
nonequilibrium H atom speed distribution toward its equilibrium Maxwe
ll-Blotzmann form. In this way the excitation function and reaction th
reshold for the reactions H + D-2 --> HD + D and H + D2O --> HOD + D c
ould be determined for the first time from the measured nonequilibrium
D atom formation rates and single-collision absolute reaction cross s
ections measured at higher collision energies.