CMPR+LOGIC

Semi-quantitative phase analysis of X-ray diffraction pattern using the software CMPR & LOGIC. As the end of the video, we can end up with the search-match analysis of phase identification, pattern indexing for crystal class, unit cell parameters, space group and crystallite size and strain.
The steps for the analysis are as follows
1. Open the CMPR software and open the data file from the working folder (where the data file is saved) by correctly selecting the file format in the Read tab of CMPR software. Ensure that the correct data is opened by visualizing the pattern in Plot window of CMPR.
2. Go to the Fit tab and Enter the Copper Kα1 (1.54056 Å) and Kα2 (1.5444 Å) wavelengths in wavelength 1 and wavelength 2 boxes.
3. Zoom one or two peaks in the Plot window and give the data range to fit the peaks by pressing Set range to Fit. In the opened pop-up press set from zoom.
*Don’t forget to press Set From Zoom after selecting data range*
4. Add the coarse position of peaks in the plot window by placing the cursor in the near maximum of the peak and by pressing key P in keyboard.
5. In the Fit tab of main window of CMPR, Refine area, position, Low background, High background, FWHM and eta values, sequentially. Don’t change the order of refinement.
6. Move to the next set of peaks by pressing Forward 1 or Forward 0.1 in the pop-up window. Do set from zoom and add peaks as given in step 4, and fit the peaks as given in step 5.
7. Repeat the steps 3, 4, 5 and 6, and fit all the peaks present in the diffraction pattern and then close the set range to fit pop-up.
8. After fitting, ensure that all the peaks are fitted in the pattern by plotting both the pattern file and peaklist1 file in Plot tab.
9. If all the peaks are fitted successfully, save the peaklist1 file as a txt file from write tab. Open the peaklist1 file from the computer’s explorer.
10. Go to the Logic tab of CMPR. Select 2theta @ and give wavelength value (1.54056 Å) under read in selected entries. Under Logic commands, go to searches and then peaks. In the opened Select by peaks pop-up, Select 2theta, wavelength and give the Copper Kα1 (1.54056 Å) under Enter peak as.
11. Then key-in the first 8 peaks from the peaklist1 file. Give the expected maximum error value (expected peak shift) in Enter one or more errors boxes. Select REMOVE previous from search under combines tables by, and peak threshold as =30% (to start with, later on we have to change this peak threshold). Select Require all of list under Multiple peaks to include all 8 peaks for search-match. Press Apply to perform search-match analysis.
12. Select the correct JCPDS reference database by reading it and visually inspecting in the plot window.
13. Note down the selected JCPDS card number and phase name in the card in this observation book.
14. Go to the Index tab, give the wavelength and open the peaklist1 in the select peak list drop-down menu. Select all three programs and press run programs.
15. Select the correct Indexing result and compare the Indexing result with the search-matched JCPDS reference database.
16. Using the correct Indexed unit cell values, search for space group in rruff.geo.arizo... by performing cell parameters and symmetry search.
17. Key in the space group in Edit cell tab and visually inspect the extincted peaks in plot window (Extincted peaks will be yellow in color). Now ensure that both the Indexed peaks and the diffraction pattern are exactly matching.
18. Note down the Unit cell parameters and Space group name in the observation book.
19. Go to the FitWidth tab, Select peaklist1 file from the drop-down menu of Select peak list. We can see the Gaussian FWHM (due to instrumental broadening) and Cauchy (or Lorentz) FWHM (due to crystallite size and strain broadening) values in the peak list.
20. Now fit profile for Gaussian U, V, W alone and then fit Lorentzian X, Y alone. Use the Lorentzian X and Y as Lx and Ly and calculate the crystallite size and strain from the formula given above. Note down the crystallite size and strain values in the observation book
21. Use the FWHM values from the peaklist1 file to calculate the weighted average crystallite size using Scherrer formula and note down the crystallite size. Compare the crystallite size values calculated from the Scherrer’s formula and the crystallite size value calculated from the Cauchy’s parameters.

[@kisshorekampara7541]

Thank you very much for the detailed explanation. I kindly request you to upload other tools also such that many students can be benefitted. Thanks a lot, sir.

[@mohamedmusthaqh356]

Thank you very much for the explanation. Can I know from where I can download this CMPR software? Thank you