Reactions of Hydrogen and Deuterium Atoms Formed in the Photolysis of Methane and Perdeuterated Methane at 123.6 nm

The photolysis of methane and perdeuterated methane has been carried out at 123.6 nm, in the presence of interceptors (deuterium in the case of methane, and hydrogen in the case of deuterated methane). The hydrogen and deuterium atoms formed are statistically in thermal equilibrium with the reaction medium; it follows that the photodissociation into CH₃ and H has a probability close to zero at 123.6 nm. In addition, it is confirmed that CH₄ and CD₄ have different photolytic behaviors insofar as the quantum yields of hydrogen and deuterium are concerned, with ${\phi }_H{\mathrm{\hspace{0.17em}>\hspace{0.17em}\phi }}_D$ .