COMPUTER-SIMULATION OF NUCLEAR MAGNETIC-RELAXATION IN DISORDERED METAL HYDROGEN SYSTEMS

Dipolar nuclear magnetic relaxation rates have been calculated with th e aid of a computer simulation of the diffusion of hydrogen between en ergy-wells in a disordered metal-hydrogen system. In the model system the disorder creates a distribution of well depths and the correlation between the well depth and its spatial position may be adjusted by a single parameter. It is possible to move between a situation in which there is no correlation between the depth and the position of the well s to one in which wells of similar depth have an increasing tendency t o be segregated. The scale of this short-range order reflects the segr egation of the energy-wells found in the random alloy model of the tra nsition metal glasses. The characteristic peak in the frequency depend ence of the relaxation rate is broadened by the presence of the distri bution and the way in which segregation enhances this effect is discus sed.