It looks like you haven't done the FT over the same k range for both data sets. If you want to compare the FT amplitudes, that is an important step. Jeremy Kropf Chemical Sciences and Engineering Division Argonne National Laboratory -----Original Message----- From: ifeffit-bounces@millenia.cars.aps.anl.gov on behalf of Scott Calvin Sent: Fri 8/21/2009 8:48 AM To: XAFS Analysis using Ifeffit Cc: Calvin, Scott Subject: Re: [Ifeffit] limits for second shell Hi Eugenio, To my eye, I strongly suspect there's real signal there. To confirm, try several different k-ranges and k-weights. If the feature persists, it is likely physical. (It may change size and shape to some extent.) --Scott Calvin Sarah Lawrence College On Aug 20, 2009, at 11:54 PM, Eugenio Otal wrote:
Hi, I have a sample of a pure Er2O3 (blue line in the attached graph) and a sample of doped ZnO with erbium that has segregated the same oxide (red line) by thermal treatmen. The signal for de segregated oxide gets noisy around k=9 because the sample is so diluted, but the radial distribution shows second shell signal, smaller than the pre oxide, but still a signal. My doubt is about how to know if the second shell is real and if that second shell can be useful to obtain information. Is there a criteria to know that? Some limit in k-space? Thanks, euG
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