Thanks for the tutorial. I have a question regarding the FWHM of the Stephens Hexagonal Peak Shape, how can we export that information from Topas? If not possible to get it directly, how we can use the fitted parameters [Stephens_hexagonal(eta,1,s400,1,s004,1,s202,1)] to calculate FWHM? Thanks.
Wow! This video is an absolute gem! It's been immensely helpful in clarifying some complex concepts for me. The explanations were clear, concise, and easy to follow, making the whole process much more manageable. I really appreciate the effort put into creating such valuable content. Please keep up the fantastic work! 👏
This is such a carefully designed tutorial! Prof. Evans illustrates so well about the very fundamental theory of Rietveld and also provides the practical tricks. It is so valuable , thank you so much!
Thank you for the tutorials. I want to mention only one point. When I install jEdit on Windows 11 I need to install the test_example files manually on the TOPAS folder, it is not existing as described in your video automatically in that folder after running the .bsh file. The .bsh file I directly run from the unzipped folder, I hope this will not cause any problems. Your websites are also a good guide! Thank you a lot!
How do I add min and max values to the cell parameter units? In my JEDit code I have "a =lpa;:10.598092` min=10 max=10.59;" which is obviously wrong as the refined value has gone above the refined value.
Dear professor Evans, Thank you so much for all the videos. Specifically, this video has helped me to distinguish that when using the FP approach, the TCHZ command line shouldn't be used (I would have kept it even after introducing the LVol_FWHM_CS_G_L and e0_from_Strain) - maybe an obvious fact, but I missed to get it before seeing this video. Kind regards, Djurdjija
Dear Prof. Evans, many thanks for your clear explanation! I also find it helpful even I have been using TOPAS for almost more than 7 years. I was not able to join the famous TOPAS school Durham and has to learn all the tips piece by piece along the way while using TOPAS. I am sure a lot of students or researchers who are using TOPAS or start to learn TOPAS will benefit from your tutorial! Looking forward to your future tutorial!
Thanks so much for the video. When I am doing refinement of XRD pattern. Sometimes, the index is not at the center of the refinement peaks, it is a bit of shifted. Could you please advice the reasons for this and how to solve it?
The best place to ask topas questions is: topas.awh.durham.ac.uk/flarum/public/ The reason is probably due to a 2-theta shift between calculated (tick marks) and experimental peak positions due to either a zero point error or a height error. These shifts are not applied to the tick marks, but are applied to the calculated pattern.
Thank you so much for your awesome explanations. You are a great professor! 3:57 How were Radius (217), Divergence (1) axial_conv (filament_length 12, sample_length 15, receiving_slit_length 12, primary_soller_angle 5.1, secondary_soller_angle 5) and slit_width (0.1) added before refinement? 4:55 Also how were LVol_FWHM_CS_G_L (1, 4489.51014, 0.89, 5424.90744, !csgc, 10000, ...) and e0_from_strain (3.57919248e-07, !sgc, 0.0001, !sls, 0.0001) added before refinement? I don't usually see these contributions each time I do refinement for my samples. Could that be because my particle sizes are in submicrons?
Best place for topas questions is: topas.awh.durham.ac.uk/flarum/public/. In general the instrument parameters would be known for your instrument, or you might determine them using a standard material. The starting values in the size/strain macros are arbitrary. I would typically start e.g. sgc and slc at small numbers (0.0001) and refine. Other quantities in the macro are fixed or reported after refinement. If your sample contribution to the peak shape is much lower than the instrument (large domains, small strain and low resolution instrument) then the instrument contributions would dominate.
Thank you so much, Prof. John Evans. I really love the way you break things down. You remain an indispensable asset in this field. You were able to answer most of my questions in this video. I find this video really helpful.
