MAX

Alain Michalowicz, Karine Provost, Jacques Moscovici, Diane Muller Institut de Chimie et des Materiaux Paris Est, CNRS and UPEC

Introduction

MAX (Multiplatform Applications for XAFS) is a new EXAFS data analysis package inspired by and replacing the old "EXAFS pour le Mac".

The main difference is that it is no more "pour le Mac" but Multi-platform : MacOSX (Universal), Windows (XP, Vista, and 7), Linux.

MAX includes all the EXAFS data analysis functions from reading raw data files to fitting single and mulitple scattering paths models. NEW : XANES normalization, FEFF mutiple scattering paths analysis, self absorption corrections in XANES and EXAFS,...and more.

Cultural Background

Absorbix reminds you the country origin of MAX package.

Cherokee is not only an Indian people. It is also one of the favorite tunes of Charlie Parker, the Be-Bop alto sax genius.

RoundMidnight is also a famous jazz tune, written by my favorite jazzman, the pianist and composer Thelonius Sphere Monk. If you haven't understood that my favorite music is Jazz, I probalby missed something !!!

MAX is the first name of a very important Jazzman, the drummer Max Roach who passed in 2007. His music will never.

Technical Details

Absorbix

Giving the chemical formula and stoechiometry of a sample, calculates the X-Ray absorbtion spectrum and optimize the quantity of matter (thickness, specific mass

Now includes solid and liquid mixing and solutions. Also absorbance of the reagent for reactive liquid media.

Self-Absorption corrections for EXAFS and XANES fluorescence spectra available.

Cherokee

1) Reads any raw data file and transform it to absorption spectrum.

2) Performs all the steps of EXAFS Data Analysis :

3) Background removal and Normalization of XANES data.

RoundMidnight

Fitting program based on the standard EXAFS formula for single and multiple scattering paths, using the CERNLIB code MINUIT

Differences and improvements from previous versions :

- improved interface with feffxxx.dat phases and amplitude files

- improved parameters constrains (especcially for multishell numbers of neighbours and Debye Waller constrains from Molecular dynamics).

- improved experimental error, qualitiy of fit factor (in k and R space) and parameters uncertainties estimators. Correlation matrix available

-improved user's interface : Online help pages, including a statisics and error course based on the IXS Standard and Criteria subcommitte error report (version 2000).

-NEW : comparison and fits between experimental EXAFS and FEFF chi.dat , chipxxxx.dat : global and partial scattering paths analysis and fit.

-Now available : Batch File driven automatic multiple fits (with automated constrains) and statistics analysis.

CRYSTALFFREV : From crystal structure to FEFF input files

Similar to Bruce Ravel's ATOMS. But with many additional options :

- Contains all the International tables of Crystallography space groups. Improved space group search by alternate full and short names and lists of symetry operations. But you can also edit custom special groups

- Import/export : CIF and PDB files

- Re-orientation of the cluster (very useful for biomolecular complexes, especcially macrocycles with axial ligands)

- Partially filled (vacancies) and shared crytallographic sites => random distribution of atoms in the cluster.

- FEFF7 (for those who need only single and multiple scattering paths phases and amplitudes) and FEFF8 formats, including XANES, SCF and Full Multiple Scattering cards.

In progress : FEFF9 cards

NEW : Straight_no-Chaser

This new member of the MAX family is a linear combinaison fit program in order to decompose a mixed spectrum in its model components.

Works on normalized XANES, complete normalized absorption or EXAFS spectra.

Linear Least Squares Fit is performed by Gauss-Jordan matrix inversion or by Single Value Decomposition

Provide statistical QF, error bars and correlation matrix.

Tools to check and minimize the correlations and improve the fit accuracy.

Two very useful options :

1) Progressive linear least squares method in order to find the best composition using three criteria : Positive coefficients, Error less than x% of the value, Lowest QF. Useful when the actual number of components among the possible model compounds spectra is unknown and some of the model spectra are highly correlated.

2) Fit of a series of N spectra (N only limited by the computer memory). Useful to fit automatically spectra issued from a Quick EXAFS experiment.



Strength and Weakness


Strength :

Weakness : missing options, for the moment ( in progress ).



Platform






Programming Language

Mainly Runtime Revolution Transcript, Roundmidnight's code, partly in Transcript, partly in Fortran


Terms

The use of source codes needs Runtime Revolution (http://www.runrev.com). They are available on demand.

Homepage

http://www.icmpe.cnrs.fr(including a free downloading page)


Contact

Alain Michalowicz - University <michalov@u-pec.fr>

Alain Michalowicz - ICMPE CNRS <alain.michalowicz@icmpe.cnrs.fr>

Citation

MAX: Multiplatform Applications for XAFS Michalowicz Alain, Moscovici Jacques, Muller-Bouvet Diane and Provost Karine, Journal of Physics: Conference Series 190 (2009) 012034-012035

SCREENSHOTS





Software/MAX (last edited 2012-06-11 21:02:06 by MattNewville)