— Alan Coelho 2017/05/18 18:01
Example use of first fitting a background, and then refining with the background fixed to refined values. The background refinement stage fits regions of the pattern that contain background only.
First Run determines background.
Second Run refines the structre with the background fixed.
num_runs 2 macro Bkg_Refine { #if (Run_Number == 0) @ #endif } XDD(ceo2) bkg Bkg_Refine 0 0 0 0 One_on_X(Bkg_Refine, 0) #if (Run_Number == 0) ' Weight non-background regions to zero weighting = If(Or( ' Regions that contain background only And(X >= 23.057, X <= 25.141), And(X >= 30.763, X <= 31.142), And(X >= 37.287, X <= 40.649), And(X >= 50.794, X <= 51.814), And(X >= 63.520, X <= 64.961), And(X >= 72.105, X <= 73.245), And(X >= 82.850, X <= 84.231), And(X >= 91.735, X <= 92.455), And(X >= 100.19, X <= 101.52), And(X >= 110.10, X <= 111.36), And(X >= 122.71, X <= 123.49), And(X >= 132.85, X <= 133.75) ), 1 / Max(Yobs+1, 1), 0 ); #else CuKa5(0.0001) Radius(173) LP_Factor(17) Full_Axial_Model(12, 20, 12, 5.1, @ 7) Divergence(1) Slit_Width(.1) bkg @ 0 0 0 0 0 One_on_X(@, 1000) Zero_Error(@, 0) STR(Fm3m) phase_name CeO2 scale @ 0.0014503208 Cubic(@ 5.41) site Ce1 occ Ce+4 1 beq @ 0.2028 site O1 x 0.25 y 0.25 z 0.25 occ O-2 1 beq @ 0.5959 CS_L(@, 300) Strain_L(@, 0.1) #endif