MEASURING DISTRIBUTIONS OF JUMP RATES IN DISORDERED METAL-HYDROGEN SYSTEMS BY NUCLEAR MAGNETIC-RELAXATION

Monte Carlo calculations of the nuclear magnetic relaxation rate in a disordered metal-hydrogen system having a distribution of jump rates a re reported. The calculations deal specifically with the spin-locked r otating-frame relaxation time T-1 rho. The results demonstrate that th e temperature variation of the rate is only weakly dependent on the di stribution and it is therefore unlikely that the jump rate distributio n can be extracted from relaxation measurements in which temperature i s the main variable. It is shown that the alternative of measuring the relaxation rate over a wide range of spin-locking field strengths at a constant temperature can lead to an evaluation of the distribution.