Open AccessFDMX : extended X‐ray absorption fine structure calculations using the finite difference method
Author(s) -
Bourke Jay D.,
Chantler Christopher T.,
Joly Yves
Publication year - 2016
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s1600577516001193
Subject(s) - x ray absorption fine structure , wave function , scattering , atomic physics , absorption (acoustics) , computational physics , range (aeronautics) , chemistry , physics , materials science , optics , quantum mechanics , spectroscopy , composite material
A new theoretical approach and computational package, FDMX , for general calculations of X‐ray absorption fine structure (XAFS) over an extended energy range within a full‐potential model is presented. The final‐state photoelectron wavefunction is calculated over an energy‐dependent spatial mesh, allowing for a complete representation of all scattering paths. The electronic potentials and corresponding wavefunctions are subject to constraints based on physicality and self‐consistency, allowing for accurate absorption cross sections in the near‐edge region, while higher‐energy results are enabled by the implementation of effective Debye–Waller damping and new implementations of second‐order lifetime broadening. These include inelastic photoelectron scattering and, for the first time, plasmon excitation coupling. This is the first full‐potential package available that can calculate accurate XAFS spectra across a complete energy range within a single framework and without fitted parameters. Example spectra are provided for elemental Sn, rutile TiO 2 and the FeO 6 octahedron.