Welcome to the FPX page at the ESRF


FPX: a package for the ab initio calculation of X-ray absorption near edge structure (XANES) using the non-muffin-tin (non-MT) multiple-scattered-wave (MSW) method.

by David L Foulis

Introduction

Theory

The MSW method derives from the work of J C Slater and K H Johnson [17] from the mid to late 1960s onwards, who adapted the KKR method, well known from solid-state theory, to bound-state calculations for molecules and clusters. Codes implementing the method were written by Smith and Johnson [18]. (A good review of all this work, and further references, may be found in Ref. [12].) A relativistic extension [20,21] of the MSW method was developed, but is not part of our present approach, since we are typically interested in systems containing atoms no heavier than first or second row transition metals.

The method was soon extended to continuum states [1] with application to electron-molecule scattering and molecular photoionization. The application to XANES was done by C R Natoli and co-workers [15], and it is from this work that our current approach was developed.

The theoretical methods used in the foregoing rely on the MT approximation. Concurrently with their development however, there was also investigation of ways to avoid this approximation. In solid-state theory the work of Williams and Morgan [19] led to considerable theoretical work and some computational implementations. For molecules and clusters we developed our non-MT approach from the work of Natoli, Benfatto and Doniach [14].

History

Status

A snapshot of the current directory tree may be found at fpx-1.0-0.tar.gz.

5 April 2002 - Completed porting the skeleton of main codes to a Linux environment. This constitutes version 1.0 (revision level 0) of FPX.

Limitations and known problems

Future improvements

References

Below are the main external references, and all of my own, related to the FPX package. For those who are particularly interested, I still have a few (p)reprints of some of them.

[1] D Dill and J L Dehmer, J Chem Phys 61 (1974) 692-9
Electron-molecule scattering and molecular photoionization using the multiple-scattering method

[2] D L Foulis, PhD thesis (University of Warwick, 1988) (unpublished)
The Effects of the Use of Full Potentials in the Calculation of X-Ray Absorption Near-Edge Structure by the Multiple-Scattered-Wave X-alpha Method

[3] D L Foulis and A-M Flank, in X-ray absorption fine structure ed S S Hasnain (Ellis Horwood, Chichester, England, 1991) pp 41-3
X-ray absorption near-edge structure calculations for small silicon oxide clusters

[4] D L Foulis, R F Pettifer and V L Jennings, in Recent Advances in Density Functional Methods Part III, eds V Barone, A Bencini and P Fantucci (World Scientific Publishing Company, Singapore, 2002)
Local density approach to real-space multiple-scattering calculations of inner-shell photoabsorption cross sections for clusters

[5] D L Foulis, R F Pettifer and C R Natoli, J Phys (Paris) Colloq 47 (1986) C8-597-602
Progress in SCF-SW-Xalpha ab initio XANES calculations for chromium hexacarbonyl based on general non-muffin-tin potentials

[6] D L Foulis, R F Pettifer, C R Natoli and M Benfatto, Phys Rev A 41 (1990) 6922-7
Full-potential scattered-wave calculations for molecules and clusters: Fundamental tests of the method

[7] D L Foulis, R F Pettifer, C R Natoli and M Benfatto, in 2nd European Conference on Progress in X-Ray Synchrotron Radiation Research eds A Balerna, E Bernieri and S Mobilio (Societa' Italiana di Fisica, Bologna, 1990) pp 27-30
Full-potential scattered-wave XANES calculations for chromium hexacarbonyl

[8] D L Foulis, R F Pettifer and P Sherwood, Europhysics Letters 29 (1995) 647-52
The Removal of the Muffin-Tin Approximation and Use of Self-Consistent-Field Electron Densities for Calculating the K-edge X-Ray Absorption Near-Edge Structure of Chlorine

[9] D L Foulis, R F Pettifer and P Sherwood, Physica B 208 & 209 (1995) 68-70
Full-potential XANES calculations for HCl using SCF electron densities

[10] D L Foulis, S J Rose and T D Beynon, Laser and Particle Beams 14 (1996) 555-60
Multicenter wavefunctions in opacity calculations for dense plasmas

[11] D L Foulis, S J Rose and T D Beynon, J Quant Spectrosc Radiat Transfer 58 (1997) 577-83
Transient multicentre electronic structure in dense plasmas

[12] K H Johnson, Advan Quantum Chem 7 (1973) 143-85
Scattered-Wave Theory of the Chemical Bond

[13] C R Natoli, M Benfatto, C Brouder, M F Ruiz Lopez and D L Foulis, Phys Rev B 42 (1990) 1944-68
Multichannel multiple-scattering theory with general potentials

[14] C R Natoli, M Benfatto and S Doniach, Phys Rev A 34 (1986) 4682-94
Use of general potentials in multiple-scattering theory

[15] C R Natoli, D K Misemer, S Doniach and F W Kutzler, 1980, Phys Rev A 22, 1104-8
First-principles calculation of X-ray absorption-edge structure in molecular clusters

[16] S J Rose, D L Foulis and P Gauthier, J Phys B: At Mol Opt Phys 31 (1998) L127-33
The effect of transient molecules on the bound-bound contribution to the radiative opacity at the centre of the Sun

[17] J C Slater and K H Johnson, Phys Rev B 5 (1972) 844-53
Self-Consistent-Field Xalpha Cluster Method for Polyatomic Molecules and Solids

[18] F C Smith Jr and K H Johnson, Phys Rev Lett 22 (1969) 1168

[19] A R Williams and J van W Morgan, J Phys C 7 (1974) 37

[20] C Y Yang and S Rabii, Phys Rev A 12 (1975) 362-9
Relativistic scattered-wave theory

[21] C Y Yang, J Chem Phys 68 (1978) 2626-9
Relativistic scattered-wave theory. II. Normalization and Symmetrization


Last updated on 6 April, 2002
Queries and comments to David Foulis (foulis@esrf.fr)