Also available (crystallography-related)

Armel Le Bail

• low_fwhm_and_rp.html - Some comments made during the search for a commercially available conventional X-ray powder diffractometer which would provide simultaneously a good resolution (low Full Width at Half Maximum) and whole pattern profile shapes well fittable by Rietveld softwares (low reliability R on profile - calculated after background subtraction). Announced on sci.techniques.xtallography and the Rietveld mailing list (1994) and recently updated (October 1996).
• rieticdd.txt - Summary of a discussion on the Rietveld Mailing list, about relations Rietveld-ICDD and more. In my opinion, the most important remark has been from Camden Hubbard (ORNL): "To me it is truly disappointing that Rietveld and simulated patterns are not beeing saved in PDF with full detail for use by ICDD customers. Clearly, a disgrace for the ICDD that this has lingered on for over a decade since a number of us recognized and proposed the need.". I fully agree with that point of view. Now do ICDD will change its policy ? Wait and see.
• OVERLAP - A quite simple software which eliminates reflections overlapping too much in a set of "observed" structure factor amplitudes extracted from a powder diffraction pattern either by the Pawley or the Le Bail methods. The next step is the structure determination by Patterson or direct methods, but do not eliminate more than 50%. The manual is inside the Fortran source, in french, sorry. Are available : overlap.exe, an executable for PC (binary ) + F77l3.eer; overlap.for, the source for ALPHA-AXP running VMS ; overlap.new, the Fortran source for PC ; pbso4x.dat, a data set for testing.
• SHELX76.ZIP - The package contains a SHELX76 PC version for MS WINDOWS 95 (32 bits executable, source, manual, test files) useful if you have not SHELXA for absorption corrections. You can recreate a .hkl file containing corrected intensities which is readable by SHELXL93 (or SHELXS86) specifying a HKLF 4 card. For those not having upgraded to WIN 95, a 16 bits version for WIN 3.11 is available as SHELX76A.ZIP, however it is a light version only able to perform absorption correction.

armel@fluo.univ-lemans.fr