how to reduce the core-hole lifetime broadening in feff8.2
Dear all, Could somebody give me a hint how to reduce the core-hole lifetime broadening in feff8.2? Do I need to change the source code? I have partial fluorescence yield XANES spectrum whose White Line is narrow than the one in the calculation. Thanks for any help Tonya
On Thursday 11 June 2009 08:58:53 am tony vitova wrote:
Could somebody give me a hint how to reduce the core-hole lifetime broadening in feff8.2? Do I need to change the source code? I have partial fluorescence yield XANES spectrum whose White Line is narrow than the one in the calculation.
http://leonardo.phys.washington.edu/feff/wiki/index.php?title=EXCHANGE and http://leonardo.phys.washington.edu/feff/wiki/index.php?title=CORRECTIONS B -- Bruce Ravel ------------------------------------ bravel@bnl.gov National Institute of Standards and Technology Synchrotron Methods Group at NSLS --- Beamlines U7A, X24A, X23A2 Building 535A Upton NY, 11973 My homepage: http://xafs.org/BruceRavel EXAFS software: http://cars9.uchicago.edu/~ravel/software/exafs/
Hi Tonya, I use the EXCHANGE card to reduce the applied broadening in my spectra. If you set the third parameter in the card to a number less than zero (up to about -5 in my experience) then the broadening is reduced and you can calculate high resolution type XANES spectra. This applies only to some inherent limit in the calculations where further reducing the parameter has no effect. You can look up the EXCHANGE card on the feff wiki as it also can be used to change the exchange model and the position of the Fermi level. Hope that helps you! Janine tony vitova wrote:
Dear all,
Could somebody give me a hint how to reduce the core-hole lifetime broadening in feff8.2? Do I need to change the source code? I have partial fluorescence yield XANES spectrum whose White Line is narrow than the one in the calculation.
Thanks for any help
Tonya
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-- Dr Janine GRATTAGE Postdoctoral Fellow, ID26 European Synchrotron Radiation Facility (ESRF) Sector 26, BP 220 6, rue Jules Horowitz, 38043 Grenoble, Cedex 9, FRANCE Tel: +33(0)4 38 88 19 30 Email: janine.grattage@esrf.fr
Hi Tony, Following Bruce's suggestion, you can reduce the core-hole broadening by making Vi negative. When you do this, note that the amount of reduction is limited by the core-hole broadening (i.e., the variable Gam_ch which is printed out in the header to xmu.dat or chi.dat). Thus for a typical case (Al) where Gam_ch=3.763E-01, you can set Vi= -0.018 in the EXCHANGE or CORRECTIONS cardds. J. Rehr On Thu, 11 Jun 2009, tony vitova wrote:
Dear�all, � Could somebody give me a hint how to reduce the core-hole lifetime broadening in feff8.2? Do I�need to change the source code? I have partial fluorescence yield XANES spectrum whose White Line is narrow than the one in the calculation. � Thanks for any help � Tonya
participants (4)
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Bruce Ravel -
Janine GRATTAGE -
John J. Rehr -
tony vitova