Re: Literature on Rietveld limitations in nano materials
Dear Rietvelders, Thank you for your numerous replies, which give me a bunch of references to read through. Please take my apologies that I'm not able to reply and say thank you to all contributors individually. With kind regards, Frank Girgsdies On 07.06.2019 15:36, Darren Broom wrote: Dear Frank With regard to accurately determining the size of small particles or nano-crystallites, have you seen this article on "Pitfalls in the characterization of nanoporous and nanosized materials" by Claudia Weidenthaler? https://pubs.rsc.org/en/content/articlelanding/2011/nr/c0nr00561d Best regards, Darren -Original Message- From: girgs...@fhi-berlin.mpg.de Sent: Thu, 6 Jun 2019 12:39:29 +0200 To: rietveld_l@ill.fr Subject: Literature on Rietveld limitations in nano materials Dear fellow Rietvelders, Could anyone point me to some nice literature which critically discusses the limitations of the Rietveld method when it comes to nano-crystalline materials (specifically in the 1 to 3 nm range)? As far as I'm aware, the core Rietveld literature seems to touch this point only in the passing. Background: To the best of my knowledge, Rietveld-derived parameters (like lattice constants or domain sizes) should not be trusted as being "physically meaningful" anymore when you fit the powder pattern of a material in the few nm range with standard Rietveld tools. My naive understanding of this problem is that the physical principles of diffraction (or rather the best way to model it) gradually change when you go from long-range ordered to medium-/short-range ordered materials. Being a Rietveld practitioner rather than a theoretician, and having no first-hand experience with WPPM and PDF methods, I am often confronted with the problem to explain to my "customers" why I can't extract trustworthy lattice constants or domain sizes from their nano-crystalline samples, especially if it seems technically possible to fit the pattern with a Rietveld program. I think it would be nice if I could cite some critical discussion, or overview article with further references, to put my finger on the problem. Especially in the catalysis community literature, my impression is that the applicability of the Rietveld method is sometimes overestimated, leading to overinterpretation of the results. Any suggestions? Best wishes, Frank Girgsdies ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++ ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++ ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re: Empyrean change in configuration
Thank you all for you help. Panalytical has already contacted me and they have offered their assisstance to solve it. I am using the following: Source Cu LFF at 45 kV 40 mA. Focusing mirror, ½º divergence slit, 0.04 rad soller slits, anti-scatter device, ½º anti-scatter slit. Sample changer R-T spinner 943006080001 Fixed anti-scatter for capillary spinner. Pixcel1D dectector 9430030 18x0x. Kind regards, Breogán De: rohlicek Enviado: martes, 11 de junio de 2019 11:46:49 Para: Cristóbal Verdugo Cc: rietveld_l@ill.fr; Breogán Pato Doldán Asunto: Re: Empyrean change in configuration Dear Breogán, most probably, you have to make alignment of the primary beam cut. If you use focusing mirror, the beam cutter should be there, see the picture here: https://drive.google.com/file/d/1SLbYfw90cikML_tE19Xp0ZHgBBNtTc9Y/view?usp=sharing Jan Dne 2019-06-11 11:17, Cristóbal Verdugo napsal: > Hi Breogan, > > Not with Panalytical but with Bruker diffractometer I had the same > problem, we are close to the direct beam. What I did was to cronstruct > a circular slit to cut the direct beam and now I can measure from 2 > degrees. > Please, feel free to contact me for help. > > Regards, > > Cristóbal > > — > Dr. Cristóbal Verdugo-Escamilla > > cristobal.verd...@csic.es > Phone. 0034 677350122 > El 11 jun 2019 11:10 +0200, Breogán Pato Doldán > , escribió: > >> Dear Rietvelders, >> >> First of all, I would like to thank you for your help. I joined the >> mailing list during the first year of my PhD studies. The Rietveld >> mailing list has proved to be a quite useful tool through these >> years. >> >> I have just arrived to a new lab and I am the only one with some >> XRPD experience. >> >> Several months ago an Empyrean from Panalytical was installed in the >> lab. The diffractometer is configured on transmisión. I have had >> some problems recording data at low angles (below 5 degrees) ¿Has >> anyone had the same problem? >> >> Best regards, >> >> Breogán Pato >> ++ >> Please do NOT attach files to the whole list >> >> Send commands to eg: HELP as the subject with no >> body text >> The Rietveld_L list archive is on >> http://www.mail-archive.com/rietveld_l@ill.fr/ >> ++ > ++ > Please do NOT attach files to the whole list > > Send commands to eg: HELP as the subject with no body > text > The Rietveld_L list archive is on > http://www.mail-archive.com/rietveld_l@ill.fr/ > ++ ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re: Empyrean change in configuration
Dear Breogán, most probably, you have to make alignment of the primary beam cut. If you use focusing mirror, the beam cutter should be there, see the picture here: https://drive.google.com/file/d/1SLbYfw90cikML_tE19Xp0ZHgBBNtTc9Y/view?usp=sharing Jan Dne 2019-06-11 11:17, Cristóbal Verdugo napsal: Hi Breogan, Not with Panalytical but with Bruker diffractometer I had the same problem, we are close to the direct beam. What I did was to cronstruct a circular slit to cut the direct beam and now I can measure from 2 degrees. Please, feel free to contact me for help. Regards, Cristóbal — Dr. Cristóbal Verdugo-Escamilla cristobal.verd...@csic.es Phone. 0034 677350122 El 11 jun 2019 11:10 +0200, Breogán Pato Doldán , escribió: Dear Rietvelders, First of all, I would like to thank you for your help. I joined the mailing list during the first year of my PhD studies. The Rietveld mailing list has proved to be a quite useful tool through these years. I have just arrived to a new lab and I am the only one with some XRPD experience. Several months ago an Empyrean from Panalytical was installed in the lab. The diffractometer is configured on transmisión. I have had some problems recording data at low angles (below 5 degrees) ¿Has anyone had the same problem? Best regards, Breogán Pato ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++ ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++ ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re: Empyrean change in configuration
Dear Breogán Pato, not that I offer some assistance, but have a word of advice. I know that PANalytical people read the list, so for them and other experts a little bit more information is required to assist with your issue. Could you please be more specific? What kind of problems you face? For example, high tail of the primary beam, complete intensity cut-off, something else? What is the configuration of your machine? Sample holder type, primary beam optics, if any, slits configuration? What kind of detector do you use? I hope that helps. Kind regards, Eduard Levin From: Breogán Pato Doldán Sent: Tuesday, June 11, 2019 12:08 PM To: rietveld_l@ill.fr Subject: Empyrean change in configuration Dear Rietvelders, First of all, I would like to thank you for your help. I joined the mailing list during the first year of my PhD studies. The Rietveld mailing list has proved to be a quite useful tool through these years. I have just arrived to a new lab and I am the only one with some XRPD experience. Several months ago an Empyrean from Panalytical was installed in the lab. The diffractometer is configured on transmisión. I have had some problems recording data at low angles (below 5 degrees) ¿Has anyone had the same problem? Best regards, Breogán Pato ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++ ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Re: Empyrean change in configuration
Hi Breogan, Not with Panalytical but with Bruker diffractometer I had the same problem, we are close to the direct beam. What I did was to cronstruct a circular slit to cut the direct beam and now I can measure from 2 degrees. Please, feel free to contact me for help. Regards, Cristóbal — Dr. Cristóbal Verdugo-Escamilla cristobal.verd...@csic.es Phone. 0034 677350122 El 11 jun 2019 11:10 +0200, Breogán Pato Doldán , escribió: > Dear Rietvelders, > > First of all, I would like to thank you for your help. I joined the mailing > list during the first year of my PhD studies. The Rietveld mailing list has > proved to be a quite useful tool through these years. > > I have just arrived to a new lab and I am the only one with some XRPD > experience. > Several months ago an Empyrean from Panalytical was installed in the lab. The > diffractometer is configured on transmisión. I have had some problems > recording data at low angles (below 5 degrees) ¿Has anyone had the same > problem? > > Best regards, > Breogán Pato > ++ > Please do NOT attach files to the whole list > Send commands to eg: HELP as the subject with no body text > The Rietveld_L list archive is on > http://www.mail-archive.com/rietveld_l@ill.fr/ > ++ > ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
Empyrean change in configuration
Dear Rietvelders, First of all, I would like to thank you for your help. I joined the mailing list during the first year of my PhD studies. The Rietveld mailing list has proved to be a quite useful tool through these years. I have just arrived to a new lab and I am the only one with some XRPD experience. Several months ago an Empyrean from Panalytical was installed in the lab. The diffractometer is configured on transmisión. I have had some problems recording data at low angles (below 5 degrees) ¿Has anyone had the same problem? Best regards, Breogán Pato ++ Please do NOT attach files to the whole list Send commands to eg: HELP as the subject with no body text The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/ ++
