On Wednesday 12 January 2005 09:38 am, Norbert Weiher wrote:
just to throw another one in :)
The more the merrier!
ATHENA has the following problem - I make a linear combination fit of two spectra and put the result in a group. Then I want to export it using the "save groups as..." and.... just get zero's in the file. Using the IFEFFIT buffer and saving the corresponding array with the write_data() command works fine - maybe there's a renaming bug of the corresponding array? Furthermore, the fit looks shifted as soon as written to an array. When I fit (the 3rd spectrum in the example with a LC of the first two) everything looks nice. The saved LC is, however, shifted compared to the one seen during the fit. Furthermore, I cannot change any parameter of this (LC) group...
You are correct on all counts. The energy shift was due to the fact that I applied the e0 shift of the unknown data group twice to the LCF data group. Oops! I am not completely sure why it was being saved as all zeros, but fixing other problems also solved that. You could not change the parameters because, long ago, I had decided to save the LCF-in-energy data as a detector group. My thought was that an artificial data group should not be analyzed like real data. There really isn't a good reason why the LCF-in-energy group should not be treated that way. For instance, it might be interesting to remove the background from the LCF-in-energy group to see if its chi(k) looks like the chi(k) of the unknown data. In any case, I changed that so now you can treat LCF-in-energy data just like real measured data. All of those fixes will be in the next release. Thanks, Norbert! B -- Bruce Ravel ----------------------------------- ravel@phys.washington.edu Code 6134, Building 3, Room 405 Naval Research Laboratory phone: (1) 202 767 2268 Washington DC 20375, USA fax: (1) 202 767 4642 NRL Synchrotron Radiation Consortium (NRL-SRC) Beamlines X11a, X11b, X23b National Synchrotron Light Source Brookhaven National Laboratory, Upton, NY 11973 My homepage: http://feff.phys.washington.edu/~ravel EXAFS software: http://feff.phys.washington.edu/~ravel/software/exafs/