Cluster formation and diffusion in a metal-hydrogen system

Hydrogen dissolved in transition metals at low temperature may form atomic clusters. Based on theoretical and experimental information on mixtures of liquid 3He and liquid 4He, the author constructs a cluster model for hydrogen and deuterium dissolved in metals. Using this cluster model, he obtains a semiphenomenological expression for the relative size of proton and deuteron clusters. Anomalous transport behavior and possible dependence of cluster formation on spin statistics are briefly discussed. (Auth.)