Rietica - a visual Rietveld program

Full text: Rietica is a Rietveld analysis program that allows interaction with the refinement process on a cycle by cycle basis using a graphic interface. Rietica was developed to aid in the creation and updating of the Rietveld input files, as well as to control the LHPM program. It is a Windows 95 based program allowing point and click control of all the functionality of LHPM. Some of the features of the Rietica program are: multiple x-ray and/or neutron histograms (datasets) allowing different scales, zeros, peak profile types and values, backgrounds, wavelengths, preferred orientations for each histogram - all of which are refinable, (1) ability to calculate and refine neutron time-of-flight (TOF) data, (2) ability to refine Δf' and Δf'' now allows extra flexibility with synchrotron diffraction data, (3) can interpolate x-ray form factors from a series of (sin(θ)/λ, f) values (eg Bessel functions), (4) a new absorption correction formula allowing μR > 1.0 for cylindrical geometry and a flat plate absorption correction based surface roughness, (5) new background functions, (6) quantitative phase analysis routines, (7) point and click data entry and program control, (8) data display and easy background and excluded region input via mouse control, (9) control of the refinement process, including automatic updating of the calculated pattern display after each step, (10) can refine using 3 strategies: a) a point and click mode of data entry and refinement control (beginners/intermediate/advanced users); b) a manual editing of the input file, but still with all the benefits of the visual interface and online graphics (intermediate/advanced users); and c) a Basic scripting language that can be used to control the refinement process and graphics output. It could be used, say, for automatic refinement of large numbers of datasets (advanced users). The program currently reads in LHPM and GSAS/Fullprof/DWBS experiment files and export in a variety of formats. The online help explains the fundamentals of the Rietveld method, the layout of the program, the input file structure, and the visual interface