I am doing Rietveld refinement by highscore plus 3.0e, after refining scale factor, background, lattice parameters, W, U, V, peak shape and atomic coordinates, the GOF is good, but there are lots of peaks in the peak list, one hkl belongs to 2 peaks and the spacing between their position is 0.1°——all peaks are no exception .
What was worse, when I calculate "size only", the result is always 27913.4, no matter which phase. For a single quartz peak in the “peak list”，the “crystallite size ？” is almost -1400 while the “crystallite size only” is nearly 30000.
What's wrong? Could anyone give me some advice?
Thank you.
There is an option to delete the k2 peaks if you did the refinement of unit cell properly
Rodrigo Uchida Ichikawa
, thank you so much.The size of quartz is not important, I was just confused by the negative numbers and doubt my refinement, what you say is so clear！
My sample was chalcopyrite after long-time high energy milling, micro-strain and the decrease of crystallite size bring in peak broadening, so there is serious overlap in adjacent chalcopyrite peaks, such as (220) &(004), (312)&(116), they look like one peak and normal fitting leads to high ESD of FWHM. I don't know whether the W-H analysis is credible or not.
W-A needs several orders of one peak, I only got (200) and (400) from this chalcopyrite sample, both of them are overlapped.
About the x-ray diffractometer, there are 2 powder diffractometers in our college. This pattern was determined by Bruker D8 advance, in Rietveld method, R exp = 1. The other one with monochromator is Rigaku Ultima IV, but there is something wrong so the pattern analyzed got quite low intensity: background 400 and max peak intensity 3000, R exp=6.
Which one should I take? I'm truly grateful for your help.
Rodrigo Uchida Ichikawa
Thank you for all your assistance.The ESD I said belongs to the main phase chalcopyrite, after milling, its adjacent peaks almost become one peak, "search peak" could only found one peak and "insert peak" lead to high ESD. I was told that the separation of highly overlapping single phase by highscore or JADE is impossible, so I don't know how to do W-H or W-A with it.
About the diffractometers, it was broken by the workers and not completely repaired, I would try your settings.
For Malvern Panalytical's HighScore Plus software suite based analysis I would recommend following webinars:
https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W20200529XRD
https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W20200611XRD
https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W20200702XRD?
https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W20200728XRD.html
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