Dear all,
I got the Cu (thin film deposited on silica,~300nm thick) fluorescence data at beamline station and fit it . For optimizing fitting quality, I tried to select and include different FEFF calculated paths and tried different sigma^2 for MS paths, I also tried different k weights, k ranges and R ranges. However, there are some problems: the amp parameter is always much less than expected 1, only around 0.57, the ss3 and ss4 values are a little high too. Besides, I chose fitting range(R space) from 1-4.4 A, but the match between data and model seemed not good enough, even for the easiest 1 shell fitting, there still remained big misfit.

I attached one best fit I could get (fit 33), I want to ask if someone can give me suggestions to help me improve my situation.

Thanks very much!