Photolysis of HI in reactive matrices at 77°K

Abstract

The photolysis of HI in films of HI, CO₂, C₂H₄ and C₃H₆ at 77°K has been studied. Quantum yields of H₂ production have been measured and the carbon-containing products analyzed. A mechanism involving initial formation of excited absorber-matrix complexes is suggested and relative rate constants of some of the subsequent reactions occurring are evaluated. Reactions occur almost exclusively in the cage, only hydrogen atoms being able to diffuse. In olefin-rich systems even hydrogen atoms do not escape the cage. Radical-radical reactions occur only to a trivial extent, if at all, in the conditions of the experiment.