Michael, If you use the same kmin for the standard and the unknown you will minimize the ambiguity. Anatoly ----- Reply message ----- From: "Michael Morrill" To: "ifeffit@millenia.cars.aps.anl.gov" Subject: [Ifeffit] S02 and k_min Date: Sun, Dec 2, 2012 1:02 PM Hello everyone, I am currently performing a simple curve fit on bulk MoS2 using an atoms file for crystalline MoS2. I've found that increasing k_min on my fit (e.g. from 2 to 4) improves the quality of the fit (R-factor from 0.028 to 0.009), but also increases S02. If I use a large enough k_min (but not so large I run out of data), S02 gets as high as 1.2 +/- 0.05. This trend is observable for single and multiple k-weight fittings. While I understand that S02>1.0 does not necessarily invalidate the fit, I am not sure how to justify which parameter values are the best seeing that "0.8http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit