Summary: Volume 197, number 6 CHEMICAL PHYSICS LETTERS 25 September 1992
Photodissociation dynamics of Hz!3isolated in krypton matrices
J. Zoval, D. Imre, P. Ashjian and V.A. Apkarian '
Department ofChemistry,Institute for Surface and Interface Science, University of California, Irvine, CA 92717, USA
Received 28 May 1992; in final form 9 July 1992
Photodissociation of HrS in krypton matrices is followed by monitoring laser-induced fluorescence from the SH photofragment.
No evidence of an energy threshold for dissociation is observed. Quantum yields of dissociation, referenced to gas-phase absorp-
tion cross sections, increase nearly linearly from 0.04+ 0.01 to 0.25 f. 0.08, in the spectral range between 266 and 193 nm (excess
energies of 0.75-2.5 eV). In addition to the SH + H direct dissociation channel, production of S atoms is observed. The latter
channel is ascribed to secondary, in-cage collisions between the SH and H fragments to produce S+H*.
As one of the simplest prototypes of condensed
phase reactive dynamics, the photodissociation of
hydrides in rare-gas solids has been the focus of both
experimental and theoretical studies in recent years
[ l- 111, The photodissociation of HI in crystalline
xenon was the first system considered [ l-4 1. Clas-
sical molecular dynamics simulations of this system
revealed that the cage exit of the H photofragment
is significantly delayed, l-3 ps, and proceeds after