Dear Husin,
Thank you very much for the papers! Best Regards, Frantisek From: Sitepu, Husinsyah [mailto:husinsyah.sit...@aramco.com] Sent: Tuesday, January 17, 2017 6:37 AM To: František Laufek Subject: RE: order of Spherical Harmonics for correction of PO Classification: Non-Business Use Dear Dr Laufek, The enclosed articles are probably useful information to answer your question. All the best for the New Year. Husin cid:image001.gif@01D21A31.2CFC5620 Husin Sitepu, PhD Saudi Aramco Research and Development Center (R&DC) Technical Service Division (TSD) Advanced Analysis Unit (AAU) Room: GB-110, Bld. 2296 P.O. Box 62, Dhahran 31311, Saudi Arabia <Tel:(+966)> Phone: (966) 13 876 3050 Email: sitep...@aramco.com Links at Google Scholar <http://scholar.google.com/citations?user=cUTV8HkAAAAJ&hl=en> ResearchGate <https://www.researchgate.net/profile/H_Sitepu/stats> cid:image002.png@01D21A31.2CFC5620 This email has been classified as Non-Business Use by Sitepu, Husinsyah on Tuesday, January 17, 2017 8:37:00 AM From: rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] On Behalf Of František Laufek Sent: Monday, January 16, 2017 12:11 AM To: rietveld_l@ill.fr Subject: order of Spherical Harmonics for correction of PO EXTERNAL: This is an external email received from the Internet. Report this message to <mailto:s...@aramco.com> s...@aramco.com if the email contains any suspicious content. _____ Normal 0 21 false false false CS X-NONE X-NONE Dear colleagues, I use Rietveld method for quantitative phase analysis. I use Topas 5 and now I have started using Spherical Harmonics for correction of preferred orientation (instead of March-Dollas correction). I mainly collect data in Bragg-Brentano geometry; samples are usually prepared by front or side-loading. My question is: Which order of Spherical Harmonics do you recommend to use for the purpose of QPA? i.e. for mineral phases like calcite, mica, feldspars, plagioclase, kaolinite? (Most atomic position are usually fixed, refined are only scale factors, unit-cell parameters, size, Debye-Waller parameters…). I know that using high order Spherical Harmonic may lead to nice fits, however with meaningless results and therefore the high orders should be used with cautions. I observe the drop of Rwp when introducing the Spherical Harmonics correction and when it becomes insignificant, than I reduce the order. E.g. for calcite, it is order of 2, for kaolinite order of 4 (i.e. using higher order lead only to insignificant drop of Rwp). Your suggestions, experiences and comments are welcome. Frantisek Laufek Czech Geological Survey, Prague Czech Republic _____ The contents of this email, including all related responses, files and attachments transmitted with it (collectively referred to as “this Email”), are intended solely for the use of the individual/entity to whom/which they are addressed, and may contain confidential and/or legally privileged information. This Email may not be disclosed or forwarded to anyone else without authorization from the originator of this Email. If you have received this Email in error, please notify the sender immediately and delete all copies from your system. Please note that the views or opinions presented in this Email are those of the author and may not necessarily represent those of Saudi Aramco. The recipient should check this Email and any attachments for the presence of any viruses. Saudi Aramco accepts no liability for any damage caused by any virus/error transmitted by this Email.
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