Dear Friends, I would like to ask a question on the interpretation of S02 in a fit. Although there has been some discussion on this parameter, I did not find exactly what I was looking for. Here it goes: To my knowledge, S02 accounts for intrinsic as well as extrinsic losses in the sample. Now, if I have two samples and determined the S02 value according to the way which Bruce has in his supplement to the FEFFIT course, I find two differing values for electrochemically prepared oxide (0.74) and crystalline gold oxide (0.92). This difference is independent of beamlines I measured and I can exclude quite safely that it is just a measurement error - it comes up with any spectrum I recorded on these systems. When discussing this with my colleagues, we interpreted the S02 difference as an indication of more disorder in case of the electrochemical system (which would well fit to my picture of the whole thing). BUT: Is there any physical reason to assign a difference in S02 (for "chemically equivalent" systems, where just the preparation is different) to a structural disorder? Regards, Norbert -- Dr. rer. nat. Norbert Weiher (weiher@chem.ethz.ch) Institute for Chemical and Bioengineering - ETH Hönggerberg HCI E 117 - 8093 Zürich - Phone: +41 1 63 3 48 32