DIFFUSION-CONTROLLED GROWTH OF HYDROGEN CLUSTERS IN METALS

We show that a simple diffusion controlled growth, with subsequent agg regation, mean field theory accounts numerically for the growth of hyd rogen clusters in certain metals (e.g. V, Nb, Zr, etc.). We also calcu late the percolation threshold for the formation of an ''infinite'' ag gregate both analytically and by a Monte Carlo simulation in a cubic l attice. The results are comparable and seem to correspond to the obser ved physical behavior.