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The Encounter Model in Impurity Diffusion. Correlation Effects in NMR
Author(s) -
Becker K. D.
Publication year - 1984
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221210108
Subject(s) - isotropy , impurity , diffusion , vacancy defect , random walk , statistical physics , chemistry , lattice (music) , chemical physics , condensed matter physics , physics , thermodynamics , mathematics , quantum mechanics , statistics , organic chemistry , acoustics
The encounter model of atomic diffusion is applied to impurity diffusion in an f.c.c. lattice using the five‐frequency model. The influence of the spatial and temporal correlation of the microscopic particle motion on NMR spectral density functions is discussed in the framework of the Torrey‐Wolf theory assuming an isotropic random walk of encounters. It is shown that for fast diffusing impurities, by combination of results from NMR and macroscopic transport experiments, a criterion can be deduced by which, under certain conditions, a vacancy mechanism can be excluded as the dominating transport process. Predictions of interstitial migration mechanisms of the Cu + ion in alkali halides based on this criterion, are in agreement with previous assignments.