Hi all, I am fitting Cu2O data. But when I fit the first shell using the first path, I got the guess value for SS parameter negative which is around -0.0028 and also the guessed value for SO2 parameter comes out to be around 0.52. Are these values logically correct as I am getting a nice fit. Also when I use the same SS parameter but with positive sign for the first shell i.e., 0.0028, the guessed value for SO2 parameter comes out to be 0.61. When I fit the higher shells by using the same SO2 and Enot value for other paths, the value of SS parameter for these paths is coming very high , i.e., 0.016 - 0.021. But the fit seems to be quiet good. Are these higher values of SS parameter correct. The resulting figure is attached. with thanks Abhijeet Gaur School of Studies in Physics Vikram University, Ujjain, INDIA.