Dear Xiaodong, Jeremy,
Isn't it equation 3 here?
http://www.nist.gov/srd/upload/jpcrd488.pdf
f1/f2 are "dispersion" numbers and f'/f" are the "anomalous" ones. The
relativisitic correction number for iron then shows up on page 221.
Best,
Jon
===
On 11/06/2015 17:27, Jeremy Karl Cockcroft wrote:
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 <mailto:j.k.cockcr...@ucl.ac.uk> or
jeremyk...@gmail.com <mailto:jeremyk...@gmail.com>
http://img.chem.ucl.ac.uk/www/cockcroft/homepage.htm
***************************************************************
On 11 June 2015 at 15:33, iangie <ian...@126.com
<mailto: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.
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