The reaction of CCl3 radicals and Cl atoms with hydrogen molecules

A small amount of H atoms are observed as products of the reaction of Cl atoms generated by photodissociating Cl2 at 351 nm in the presence of H2. A much larger H atom concentration is detected when a mixture of H2 and CCl4 is photodissociated at 193 nm with an average kinetic energy of 6.5±0.5 kcal/mol. The reactant is shown to be the vibrationally hot CCl3 radical. In the reaction of CCl3 and Cl atoms with HD the atomic H/D product ratios are 1.47±0.16 and 0.59±0.11, respectively. The former result is in accord with the theory of Johnson et al. [J. Chem. Phys. 94, 2749 (1991)] that for kinematic reasons the D end of the HD molecule is more reactive unless the HD molecule is strongly rotating. The F and Cl atoms which give H/D ratios less than 1 when reacting with HD are special cases for which higher J states of HD are still reactive.