Download FDMNES User's Guide

FDMNES User’s Guide
Introduction
The FDMNES program calculates the spectra of different spectroscopies related to the
real or virtual absorption of x-ray in material. It gives the absorption cross sections of photons
around the ionization edge, that is in the energy range of XANES in the EXAFS. The
calculation is performed with all conditions of rectilinear or circular polarization. In the same
way, it calculates the structure factors and intensities of anomalous or resonant diffraction
spectra (DAFS or RXS ). FDMNES also allows the comparison of the simulated spectra to
experimental ones with the help of objective criteria.
The code uses two techniques of monoelectronic calculations. The first one is based on
the Finite Difference Method (FDM) to solve the Schrödinger equation. In that way the shape
of the potential is free and in particular avoid the muffin-tin approximation. The second one
uses the Green formalism (multiple scattering) on a muffin-tin potential. This approach can be
less precise but is faster. The program is partially symmetrized. Symmetry operations are
calculated automatically.
The next section contains the practical informations to run the program and in
particular the description of the indata files. An introduction to x-ray spectroscopies is
available in French.
The FDMNES program can be freely downloaded at the web address:
http://www.neel.cnrs.fr/fdmnes
In case of publication related to the use of the program thanks to cite:
Y. Joly
"X-ray absorption near edge structure calculations beyond the muffin-tin approximation"
Phys. Rev. B 63, 125120 (2001).
The FDMNES program highly benefited from the scientific contribution of Calogero
Natoli who has provided a constant and essential help. He is in particular at the origin of all
the developments using the multiple scattering theory and the extensions to resonant
diffraction and magnetism. The program also benefited from the expertise of Delphine
Cabaret, Hubert Renevier, Sergio Di Matteo, Christian Brouder and Emilio Lorenzo, without
whom different advances would have not been realized. Finally, this work has been made
greatly easier with the support of Denis Raoux.
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