Van Vleck second moments and hydrogen diffusion in YH2.1-measurements and simulations

: Goc R, Zogal OJ, Vuorimaki AH, Ylinen EE

Publisher: ACADEMIC PRESS INC ELSEVIER SCIENCE

: 2004

Solid State Nuclear Magnetic Resonance

SOLID STATE NUCLEAR MAGNETIC RESONANCE

: SOLID STATE NUCL MAG

: 25

: 1-3

: 133

: 137

: 5

: 0926-2040

DOI: https://doi.org/10.1016/j.ssnmr.2003.03.009

In these preliminary studies, the Monte Carlo simulations were performed for tetrahedral-octahedral exchanges while direct tetrahedral-tetrahedral jumps were neglected for simplicity. Three models of hydrogen diffusion, differing in the maximum jump lengths allowed for a given model, were considered. These lengths were taken as the distances from the hydrogen attempting to jump to the first (INN), second (2NN), and third (3NN) nearest neighbor position able to accept the jumping atom. Assuming the same attempt frequency nu(0) = 6.0 x 10(12) s(-1) for all three models, the activation energies giving the best fit to experimental data were 0.5, 0.54, and 0.55 eV for 1NN, 2NN, and 3NN models, respectively. (C) 2003 Elsevier Inc. All rights reserved.

Physical sciences