Journal of Chemical Physics, Vol.105, No.2, 451-458, 1996
Cage Exit Probability Versus Excess Energy in the Photodissociation Matrix-Isolated HCl
Dissociation efficiencies for excitation of the repulsive A (1) Pi state of HCl were recorded in Xe, Kr, and Ar matrices for photon energies between 5 and 10 eV from the content of dissociation products and quantum efficiencies were derived with the absorption spectra. Influence of temperature and preparation conditions was investigated. The quantum efficiency rises monotonically in Xe from an excess energy of 1.4 eV above the gas phase dissociation energy on, saturates around 2.4 eV and remains then essentially constant up to 4 eV. In Ar and Kr, it saturates around 2 eV and in Ar an absolute efficiency of about 0.18 is determined at 3.7 eV. Results of molecular dynamics calculations and a statistical model agree qualitatively but the observed saturation at low excess energies is not well described and the absence of a temperature effect in Ar needs further consideration.