Direct Evidence for the Tunneling Reaction HD+D->H+D2 in the Radiolysis of a D2-HD Mixture at 4.2 K

Article abstract of DOI:10.1021/j100275a009

When a D2-HD (15.6 mol percent) mixture is γ-irradiated at 4.2 K, D and H atoms are produced and can be measured by ESR spectroscopy.ESR measurement has been performed at the very low microwave power level of 10^-3 μW which does not result in saturation of the signals from hydrogen atoms.The amounts of H atoms increase gradually upon storage of the irradiated samples at 4.2 K while the amounts of D atoms decrease complementarily.The result indicates clearly the occurence of the HD+D->H+D2 reaction, caused by quantum mechanical tunneling.Since the decrease in D-atom yields upon storage of the irradiated sample is larger than the increase in H-atom yields, some of the D atoms recombine with other D or H atoms.