Hi Xiaodong, I think that the numbers quoted for f' in the second case have had 26e (atomic no.) added to them, i.e. it refers to the total dispersion value for the real component (as opposed to the imaginary component). Given that the numbers quoted are close to an absorption edge, then the remaining differences are not unexpected depending on source and precise energy quoted. If graphs of the data are plotted with Z subtracted, then they look very similar apart from the precise value of the minimum of f' at the absorption edge itself. Just my thoughts on it... Jeremy Karl. *************************************************************** Dr Jeremy Karl Cockcroft Department of Chemistry (University College London) Christopher Ingold Laboratories 20 Gordon Street London WC1H 0AJ United Kingdom +44 (0) 20 7679 1004 (laboratory) j.k.cockcr...@ucl.ac.uk or jeremyk...@gmail.com http://img.chem.ucl.ac.uk/www/cockcroft/homepage.htm ***************************************************************
On 11 June 2015 at 15:33, iangie <ian...@126.com> wrote: > Dear Rietvelders, > > I am little confused about the term "Anomalous scattering factor" and > "Dispersion coefficients". > "Anomalous scattering factor" can be found here > http://skuld.bmsc.washington.edu/scatter/AS_form.html > "Dispersion coefficients" can be found here > http://www.cxro.lbl.gov/optical_constants/asf.html > > Their numbers are quite different: e.g. Fe @ CrKα: f0=18.474, Δf'=-1.6 Δf"=0.9 > ; however, the corresponding dispersion coefficients are f' ~24.6808 and > f" ~0.759346 > Can anyone explain their relationship? > > Thanks! > -- > Yours Sincerely, > Dr. Xiaodong(Tony) Wang > XRD Application Scientist > Bruker Singapore Pte. Ltd. > > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > Please do NOT attach files to the whole list <alan.he...@neutronoptics.com > > > Send commands to <lists...@ill.fr> eg: HELP as the subject with no body > text > The Rietveld_L list archive is on > http://www.mail-archive.com/rietveld_l@ill.fr/ > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > >
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