XAFS Data Analysis Program

XDAP is an easy to use program for complete analysis of X-ray Absorption Spectra. All steps of data-analysis can be carried out in k- or r-space. XDAP has extensive plotting capabilities and incorporates an editor for the parameters that describe the model EXAFS. All numbers considered necessary for publication of results by the Committee on Standards and Criteria in X-ray Absorption Spectroscopy are generated automatically [Jpn. J. Appl. Phys. 32-2 (1993) 877].

• Datafiles from the SRS, NSLS, SSRL, ESRF and Photon Factory are recognized and read automatically.
• Any file with energy and absorption values tabulated in columns can be read.
• Any file with energy and signals from individual detectors can be read. Signals of multiple channel fluorescence detectors can be added.
• Reads total absorption files from Feff 6 , Feff 7, and Feff 8.
• Reads the binary output file from Feff 7 and Feff 8.
• Reads the chi.dat file from any Feff version.
• Calibration of the energy axis with either a transmission or fluorescence calibration signal is possible.
• "Modified Victoreen" and polynomial PreEdge prescriptions for transmission and fluorescence experiments.
• Semi automatic background subtraction using a sophisticated cubic spline.

Analysis of Spectra with Several Scattering Paths

• Works with experimental and theoretical (McKale, FEFF) references.
• Reads the binary datafiles generated by Feff 7 and allows the user to choose one of the scattering paths stored in this file.
• Refinement of parameters in k- or r-space, thereby circumventing the need for Fourier filtering.
• Build in editor for parameter values.
• Build in graphics for evaluating the quality of fits. Here you can also look at any set of contributions to your model and use the difference file technique.
• Uses analytical partial derivatives during the refinement of parameters. This speeds up calculations by up to 80 %.
• You can define bounds on variables. Get rid of those runaways!
• Calculation of errors in parameters in k- or r-space.
• Statistical tests for the selection of the best model for a given dataset.
• Phase- and log-ratio fits with up to four cumulants for the analysis of disordered systems.
• Ability to fix the ratio of parameters in different shells. This is a great time saver when spectra of an absorber with a know surrounding are analyzed.
• Ability to fix the sum of parameters in different shells. This is very usefull when one needs to find the ratio of several types of neighbours and knows the total number of neighbours.

Other

• Phase- and log-ratio fits with up to four cumulants for the analysis of disordered systems.
• Determination of white line areas by either comparison with an experimental spectrum, Feff total absorption calculations or using the arctangent + Lorentz prescription.
• Principal Component Analysis (PCA) can be applied to XANES, EXAFS and Fourier Transforms. A nice introduction to the use of PCA in XAS is given in the paper by M.J. Fay et al., Mikrochimica Acta, 109 (1992) 281 - 294.

Windows GUI Features

• Printing to any Windows compatible printer.
• XDAP for Windows will automatically use your full screen and screen resolution.
• Instant access to Zoom, Print, and Save in all plots.