Open Access1H NUCLEAR SPIN RELAXATION CAUSED BY DIFFUSION IN HfV2·Hx THE MODEL OF RANDOM WALK TO NEAREST NEIGHBOR SITES
Author(s) -
Datong Ding,
Chen Huan-Jin,
Zhenya Guo,
Qinhan Jin,
Zhou Da-Ming
Publication year - 1988
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.37.1859
Subject(s) - heteronuclear molecule , homonuclear molecule , random walk , relaxation (psychology) , physics , dipole , diffusion , statistical physics , condensed matter physics , nuclear magnetic resonance , thermodynamics , quantum mechanics , molecule , nuclear magnetic resonance spectroscopy , statistics , mathematics , psychology , social psychology
The dominent factors affecting the nuclear spin relaxation of 1H in HfV2·Hx hydrides are dipolar couplings. The important theoretical problem is the calculation of spectral density functions for the fluctuation of the dipolar couplings caused by the diffusive motion of 1H in the host lattice. We extended Torrey's theory, based on the model of random walk to nearest neighbor sites for homonuclear dipolar interaction, to the case that both homo- and heteronuclear interactions are existent. Then we calculated the GHH(k, y) and GHV(k, y) for determining the spectral densities JqHH(ω) and JqHV(ω) (q = 0, 1,2) according to the structure constants and H occupations of HfV2 ·Hx obtained from neutron diffractions. Using our theory and data derived from previous work of others, we analyzed the activation energy and the attempt frequency of 1H on interstitial sites and found that our results are satisfactory as compared with the conclusion derived from the phenomenological theory.