3.014 Derivative Structures Data Analysis using PANalytical X Pert HighScore Plus v3.0

Transcription

1 3.014 Derivative Structures Data Analysis using PANalytical X Pert HighScore Plus v3.0 For most analyses, you will need to open the data and the corresponding entry in the reference database. You will then be able to do the analysis necessary for the lab. 1) Open the experimental data a) Select menu File > Open b) Find the data file, with a *.xrdml extension, in the folder C:\temp\3014 Derivative Structure 2) Load the reference pattern a) Select menu Reference Patterns > Retrieve Pattern By > Reference Code b) In the window that opens, type the reference code and then click Load c) After the reference pattern is loaded, click Close in the retrieval window Sample Filename Reference Number Al Al.xrdml CsCl CsCl.xrdml CuFeS 2 CuFeS2.xrdml C 60 C60 Fullerene.xrdml Fe Fe.xrdml NaCl NaCl.xrdml Si Si.xrdml SrTiO 3 SrTiO3.xrdml ZnS ZnS.xrdml Polyethylene Polyethylene.xrdml CeO 2 CeO2 as received.xrdml CeO2 500C-1hr.xrdml CeO2 650C-1hr.xrdml CeO2 800C-1hr.xrdml pg. 1

2 The program HighScore Plus has two work areas. Main Graphics, on the left, allows you to compare your data and the reference pattern. Left-click and drag to zoom in on a region; double-click to unzoom. Lists Pane, on the right, gives you additional information and the results of your analysis. There are different tabs in the Lists Pane to give you access to different information. After loading a reference card, you can open it to read information such as the crystal system and lattice parameter: 1) In the Lists Pane (right side of screen) select the Pattern List tab 2) Double-click on the entry for the reference pattern 3) The Reference Pattern window will open 4) When done, close the reference card by clicking on the Close button in the lower right corner To adjust the height of the reference pattern sticks: 1) In the Lists Pane (right side of screen) select the Pattern List tab 2) Click once on the entry for the reference pattern to highlight it 3) In the Lists Pane (right side of screen) select the Object Inspector tab 4) Use the Manual Scale slider (near the top) to change the height of the reference pattern 5) You can also change the Color of the stick pattern overlay in this window To save the graphic image: 1) select menu File > Save As 2) set the Save as type to JPEG bitmap graphics (*.jpg) 3) Select a file location and enter a File name. 4) Click the Save button pg. 2

3 Calculating Lattice Parameters In order to calculate the lattice parameter of the material based on the experimental data, you need to precisely determine the position of a diffraction peak. This is done by profile fitting. a) Manually insert a peak i) Click and drag in the main graphics window to zoom around a strong diffraction peak, including a little bit of background around the peak ii) Select menu Treatment > Insert Peak iii) Position the cursor in the main graphics window so that it matches the approximate position and height of the data, then left-click to insert a peak iv) Select menu Treatment > Insert Peak to turn the cursor off b) Profile fit the peak i) Select menu Treatment > Profile Fit > Fit Profile > Linear Bkg ii) You should see a calculated peak profile in blue overtop the experimental data in red. If you don t, select menu View > Display Mode > Show Calculated Profile to see the full profile fit peak iii) If the calculated profile does not fit very well, run the profile fitting again by selecting Treatment > Profile Fit > Fit Profile > Linear Bkg c) Record the Peak Information i) In the Lists Pane (right side of screen) select the Peak List tab ii) In the Peak List, information is listed for both K-alpha1 and K-alpha2 peaks. To remove the K-alpha2 peaks, right-click in the Peak List and select Delete All K-alpha2 Peaks from the pop-up menu. iii) Record the peak position from the column Pos. [ 2Th.] and the Miller indices (hkl) from the main graphics window. To save the graphic image: 1) select menu File > Save As 2) set the Save as type to JPEG bitmap graphics (*.jpg) 3) Select a file location and enter a File name, then click the Save button. pg. 3

4 Calculating the Crystallite Size The crystallite size of a sample can be calculated based on the diffraction peak width using the Scherrer formula. In order to calculate the crystallite size from CeO2 that has undergone different thermal cycles. 1) Open a file and reference pattern for CeO 2 as described on page 1. 2) Manually insert a peak a) Click and drag between 20 and 40 2Th in the main graphics window to zoom around the first two diffraction peaks b) Select menu Treatment > Insert Peak c) Insert two peaks at ~28.5 and ~30 2Th by positioning the cursor in the main graphics window so that it matches the position and height of the two experimental peaks, then left-click to insert a peak d) Select menu Treatment > Insert Peak to turn the cursor off 3) Profile fit the peaks a) Select menu Treatment > Profile Fit > Fit Profile > Linear Bkg b) You should see a calculated peak profile in blue overtop the experimental data in red. If you don t, select menu View > Display Mode > Show Calculated Profile to see the full profile fit peak c) If the calculated profile does not fit very well, run the profile fitting again by selecting Treatment > Profile Fit > Fit Profile > Linear Bkg 4) Record the Peak Information a) In the Lists Pane (right side of screen) select the Peak List tab b) In the Peak List, information is listed for both K-alpha1 and K-alpha2 peaks. To remove the K-alpha2 peaks, right-click in the Peak List and select Delete All K-alpha2 Peaks from the pop-up menu. c) Record the peak positions from the column Pos. [ 2Th.], the peak width from the column FHWM Left [ 2Th], and the Miller indices (hkl) from the main graphics window. i) The instrumental contribution to peak width at 28 2Th is 0.09 pg. 4

5 Calculating the Percent Crystallinity in Polyethylene For polyethylene, you will want to calculate the percent crystallinity. To do this, you must profile fit the two diffraction peaks and the amorphous hump between 15 and 25 2Theta. 1) Open the file polyethylene.xrdml 2) Select menu View > Set Manual Ranges (found near bottom of the menu) 3) In the window that opens, enter the Start pos to 12 and the End pos to 29. Click OK. 4) Insert peaks for profile fitting: a) Select menu Treatment > Insert Peak b) Left-click in the main graphics window to insert three peaks i) Insert peaks for the diffraction peaks at 21.4 and Theta. ii) Insert a peak for the amorphous hump at ~20 2Theta. c) Select menu Treatment > Insert Peak to turn the cursor off 5) Profile fit the peaks a) Select menu Treatment > Profile Fit > Fit Profile > Linear Bkg b) You should see a calculated peak profile in blue overtop the experimental data in red. If you don t, select menu View > Display Mode > Show Calculated Profile to see the full profile fit peak c) If the calculated profile does not fit very well, run it again by selecting Treatment > Profile Fit > Fit Profile > Linear Bkg 6) Record the peak information a) In the Lists Pane (right side of screen) select the Peak List tab b) In the Peak List, information is listed for both K-alpha1 and K-alpha2 peaks. To remove the K-alpha2 peaks, right-click in the Peak List and select Delete All K-alpha2 Peaks from the pop-up menu. c) For each peak, record the position and area from columns Pos [ 2Th] and Area [cts* 2Theta] in the Peak List d) For the crystallinity calculation: i) Area(crystalline) is the sum of the areas of the diffraction peaks at ~21.4 and Theta. ii) Area(amorphous) is the area of the peak at ~20 2Theta. pg. 5

6 To view a crystal structure a) in the Lists Pane (right side of screen) select the Pattern List tab. b) Right-click on the row of information for the reference pattern. Select Convert Pattern to Phase from the pop-up menu (this item appears about 2/3 s down the menu) c) In the Lists pane, select the tab Structure Plot d) Click Update Plot e) You can rotate the image by click and dragging the cursor. f) You can save the image as a bitmap by clicking on the Floppy Disk icon in the toolbar inside the Structure Plot area in the Lists Pane How to make a Comparison Plot 1) Open one data set using the menu File>Open 2) Insert additional data sets by using the menu File>Insert a. Navigate to the folder C:\temp\3014 Derivative Structure b. Select the data sets that you want to insert. You can select several data sets to insert by holding down the CTRL key as you click on the files. c. Click on the Open button 3) There are tabs below the Main Graphics window that allow you to select different views for the multiple data sets. a. The Compare view shows all of the data sets overtop each other. This view works well if all samples diffracted with similar intensity. b. The 2D view shows each data set in its own plot. This view is better if the diffraction patterns for different samples have very different intensities. c. The Analyze view will only show you the primary pattern, not any of the additional patterns. 4) To save the graphic image, select menu File > Save As pg. 6

7 Miscellaneous Options and Controls To read the agreement indices which tell you how good the profile fit is o in the Lists Pane (right side of screen) select the Refinement Control tab. o Double-click on Global Variables, which will take you to the object inspector o Find and expand the section Agreement Indices o R profile and Weighted R profile are the residuals that tell you how well the calculated profile fits your data (a good fit is below 10%) To change the y-axis between linear and square root scale, select menu View > Display Mode > Y-Axis To change the widths of lines: o select menu Customize > Document Settings, o select the Graphics Display tab. o Change the widths and then click Apply to see the change To change the color of the scan: o in the Lists Pane (right side of screen) select the Scan List tab. o Double-click on the scan title, which will take you to the object inspector. o change the Line Color and other elements as you like pg. 7