Hello,

I have observed changes in fixed parameters while running a pre-edge peak fit in XAS Viewer. I first run a baseline fit. This provides a good match to the data in the baseline fitting region. I would like to subtract the baseline from the data and then numerically integrate the data. In order to export the baseline fit and data, I fix all of the fitting parameters for bline and bpeak and then click "fit model". This generates a baseline and fit that no longer match the data well in the baseline fitting region. Additionally, in the "Fit Results" window, the reported best-fit values of the fixed parameters are slightly different from the values reported in the "Value" field after the baseline fit, to which they were fixed. This appears to be the result of rounding of the baseline fit parameters at some point after the baseline fit. For example bline_slope was fixed to "-0.0024752483" but the best-fit value is "-0.00247500". I realize I am using XAS Viewer in a way that it was not exactly designed for, and perhaps no one anticipated someone fixing a parameter out to 10 decimal places. However, what I am doing still seems reasonable, and I would greatly appreciate it if XAS Viewer could be updated so that all digits entered in the Value field for a fixed parameter will be maintained for the fit. I am happy to provide a project file and instructions to reproduce my observation if they would be helpful.

Thank you,

George