work on rietveld refinement issue #4

andrewrgarcia · Feb 5, 2023 · 326182b · 326182b
1 parent 3dbb504
commit 326182b
Show file tree

Hide file tree

Showing 3 changed files with 30 additions and 3 deletions.
diff --git a/literature.md → information.md b/literature.md → information.md
@@ -1,4 +1,21 @@
-## Rietveld refinement
+# Rietvelt refinement reference
+
+## FullProf how to
+
+[https://www.youtube.com/watch?v=GI3N3HVN3xc](https://www.youtube.com/watch?v=GI3N3HVN3xc)
+
+3 files
+	CIF file - reference model
+	XRD file - collected in very slow scan rate
+	IRF file - (optional)
+
+## structure factor
+
+[https://www.researchgate.net/post/How-can-I-estimate-the-uncertainty-in-structure-factors-derived-from-X-ray-diffraction-experiments](https://www.researchgate.net/post/How-can-I-estimate-the-uncertainty-in-structure-factors-derived-from-X-ray-diffraction-experiments)
+
+
+
+## articles
 
 Rietveld, H.M. (1969), A profile refinement method for nuclear and magnetic structures. J. Appl. Cryst., 2: 65-71. [https://doi.org/10.1107/S0021889869006558](https://doi.org/10.1107/S0021889869006558)
 
@@ -22,4 +39,3 @@ Diffraction Line Profiles in the Rietveld Method
 Paolo Scardi
 Crystal Growth & Design 2020 20 (10), 6903-6916
 [DOI: 10.1021/acs.cgd.0c00956 ](https://pubs.acs.org/doi/10.1021/acs.cgd.0c00956)
-
diff --git a/powerxrd/main.py b/powerxrd/main.py
@@ -247,7 +247,6 @@ def Rietveld(self,verbose=True, show=True):
         s = 'scale factor'
         m_K = 'multiplicity factor'
         L_pK = 'Lorentz-Polarization factor'
-        F_K = 'Structure Factor'
         phi = 'Reflection Profile function'
         Theta_k = '2\theta_k: the calculated position of the Bragg peak corrected for the zero-point shift of the counter (Rietveld 1969)'
         P_K = 'Preferred orientation'
@@ -256,6 +255,18 @@ def Rietveld(self,verbose=True, show=True):
 
         K = []  # Miller indices (hkl)
 
+        imag_i = 1j
+
+        hkl = [1,1,1]
+
+        N_j = 'Nj is the site occupancy divided by the site multiplicity'
+        f_j = 'fj is the atomic form factor'
+        x_j,y_j,z_j = 1,1,1     # xj , yj and zj are the atomic positions 
+        M_j = 'M j contains the thermal contributions (atomic displacements)'
+
+        'Structure Factor'
+        F_K = N_j * f_j * np.exp ( 2 * np.pi * imag_i ) * np.dot(hkl,[x_j,y_j,z_j]) * np.exp(1) - M_j 
+
 
         y_cal = 0
         for i in K:

diff --git a/literature/rietveld-refinement → rietveld-refinement b/literature/rietveld-refinement → rietveld-refinement