Jens: This example may help you understand your problem: if compound a) has a small fraction of metal Cu mixed with a large fraction of oxidized Cu, while a compound b) has it the other way around, then the main (1s - 4p) absorption peak in compound a) will be smaller than in b) after edge step normalization. Edge step normalization allows to view all features in XANES and EXAFS regions as if caused by an x-absorption process in a singe atom located in a concentration-average environment of all species in the sample that contain that element. Thus, the edge step normalization does have sensitivity to the composition of the sampe. Or, I misunderstood your question? Anatoly ----- Original Message ----- From: ifeffit-bounces@millenia.cars.aps.anl.gov To: ifeffit@millenia.cars.aps.anl.gov Sent: Wed Oct 29 10:02:54 2008 Subject: [Ifeffit] Normalization of XANES spectra Hi everyone, I have a general question: I know Normalizing is something we do so that we can compare samples measured under different experimental conditions (removes the effect of different gains ...) but I have problems in understanding and applying normalization when also quantitative conclusions are needed when comparing different spectra. If I have two XANES spectra (a) and (b) measure under the same conditions but with different concentration of the absorbing atom with in different molecules.If both normalized spectra show a peak 1 , but this peak is higher in intensity in spectrum (a) than in spectrum (b), does this mean that compound which produced peak 1 is also absolute higher in concentration in sample/spectrum (a) or do I loose this information after normalization? Or can I just say: in the normalized spectrum (a) peak 1 is higher than peak 2 suggesting that the compound leading to peak 1 is more abundant (just relative proportions).But I can't say: The intensity of peak 1 in the also normalized spectrum 2 is lower than in spectrum one, Therefore, the compound leading to peak 1 is less abundant in spectrum/sample 2. ???? I hope somebody can help me to understand this issue. Thanks a lot, jens -- Jens Kruse Institute for Land Use Faculty for Agricultural and Environmental Sciences Rostock University Justus-von-Liebig-Weg 6 18059 Rostock GERMANY Phone: +49(0)381-498 3190 _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit