Brian Toby’s EXPGUI: Le Bail fitting to get the whole profile fit the data before structure refinement
Various tricks may be required.
Fix the “Scale Factor”. It is meaningless to refine the scale factor when doing a Le Bail fit.
Brian Toby trick: Run zero cycles until the intensities roughly match before releasing any other parameters (peak profile, unit cell, zero offset)
Fit the background manually with Chebyshev coefficients within bkgedt instead of refining the background will save a lot of pain
Running Powpref resets the Le Bail intensities and you have to turn off all parameters and rematch the intensities with the pattern : so you would normally avoid doing this unless you make a change to the “spacegroup” or other relevant parameters such as the “peak cutoff”