Fixing Background

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)
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```