IFEFFIT is a program and programming library for analyzing x-ray absorption fine-structure (XAFS) data. As its name may suggest, IFEFFIT1 gives an interactive method for fitting XAFS data using calculations from FEFF, and is based on the fitting program FEFFIT of the UWXAFS3.0 Analysis Package. There have been significant additions to FEFFIT, and the user interface has been completely rewritten.
IFEFFIT is a complete XAFS analysis package, allowing general data manipulation, analysis, and plotting, as well as meeting the unique demands of analyzing XAFS data. For those of you familiar with the UWXAFS3.0 Package, IFEFFIT combines the functionality of AUTOBK and FEFFIT and adds many more features. A major goal of IFEFFIT is to make a graphical user interface (GUI) for XAFS analysis, but IFEFFIT is not simply a GUI program by itself. It is, instead, a command-based library that can be run either as a command-line program or called from other programs, including both graphical and non-graphical interfaces. At this writing, an enhanced command-line program named G.I.FEFFIT is distributed with IFEFFIT, and the GUI programs ATHENA, ARTEMIS, TKATOMS, and SIXPACK make use of IFEFFIT.
This Reference Guide describes the commands and syntax of IFEFFIT, and is intended for people who want direct access to the underlying 'IFEFFIT engine', either directly from the command-line program or through their analysis scripts. While some people may be satisfied with high-level GUI wrappers, many scientists appreciate a simple, scriptable command-based interface to a set of core XAFS analysis routines. The commands and syntax described here are an attempt to provide such an interface.
This guide starts with an example in Chapter 2 and then discusses the general syntax and structure of the commands in Chapter 3. The next several chapters give more in-depth information about input and output files, plotting, fitting XAFS data with FEFF calculations, and fitting non-XAFS data to simple functions. Chapter 9 lists all the commands and their complete syntax. Chapter 10 discusses writing simple macros for IFEFFIT and more complicated scripts using scripting languages.
In addition to this Reference Guide, there is also The IFEFFIT Tutorial which gives a more gentle introduction to IFEFFIT. More information about IFEFFIT, including installation instructions, further examples, a searchable mailing list, and the other documention are available with the source code and at the IFEFFIT web site: http://cars9.uchicago.edu/ifeffit/