| Numéro |
J. Phys. IV France
Volume 7, Numéro C2, Avril 1997
Proceedings of the 9th International Conference on X-Ray Absorption Fine Structure
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|---|---|---|
| Page(s) | C2-155 - C2-156 | |
| DOI | https://doi.org/10.1051/jp4/1997148 | |
J. Phys. IV France 7 (1997) C2-155-C2-156
DOI: 10.1051/jp4/1997148
Ab Initio XAFS Debye-Waller Factors
A.V. Poiarkova1 and J.J. Rehr21 Physics Department, Box 351560, University of Washington, Seattle, WA 98195-1560 U.S.A.
2 Physics Department, Box 351560, University of Washington, Seattle, WA 98195-1560, U.S.A.
Abstract
An efficient, finite temperature, equation of motion method is introduced for calculations of the meansquare
relative displacements σ2 in XAFS Debye-Waller factors. Instead of calculating projected densities of modes,
the calculations are based on the displacement-displacement correlation function and done in real time, over a few
vibration cycles. Results for the Debye-Waller factors are found to be accurate to within about 15% percent at
all temperatures. We also discuss how force constants used in the calculations can be obtained from ab initio
Car-Parrinello/molecular dynamics calculations. Tests of the method are presented based on the Wiggs-Jónsson
plane-wave pseudopotential code [Comp. Phys. Comm. 87, 319 (1995)]. Application to XAFS Debye-Waller factors
in biological molecules is discussed.
© EDP Sciences 1997