[GSAS-II] Over estimation of crystallite size

[davide levy]

As far you know, the precision of the crystal size calculated by Xrpd is lower than other method. 

Now I am not in my office so I do not have the exact reference, if I remember right there is something in Powder Diffraction: Theory and Practice. 

 

From: gsas-ii-bounces at aps.anl.gov <gsas-ii-bounces at aps.anl.gov> On Behalf Of Victor Zenou
Sent: Thursday, August 23, 2018 8:42 PM
To: gsas-ii at aps.anl.gov
Subject: [GSAS-II] Over estimation of crystallite size

 

Dear everyone. 

I used GSAS-II to estimate crystallite size from lab PXRD. The sample was annealed anatase.

Before annealing all results (GSAS-II, Debye function analysis (DFA), GSAS and HRTEM) were the same, about 5nm.

After annealing GSAS-II gave 19/21(0.3) nm, while DFA gave 14(5) nm and HRTEM gave 12(3).

Does anyone got the same , what seem to be, over estimation by GSAS-II?

Of course, using standard deviation give not so far results.

Best regards,Victor

 

בתאריך יום ה׳, 23 באוג׳ 2018, 20:00, מאת ‏<gsas-ii-request at aps.anl.gov <mailto:gsas-ii-request at aps.anl.gov> >:

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Today's Topics:

   1. Help with refining instrumental parameters (Emily Siska)
   2. Re: Help with refining instrumental parameters (Sergey Ushakov)


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Message: 1
Date: Wed, 22 Aug 2018 10:58:38 -0700
From: Emily Siska <siskae at unlv.nevada.edu <mailto:siskae at unlv.nevada.edu> >
To: gsas-ii at aps.anl.gov <mailto:gsas-ii at aps.anl.gov> 
Subject: [GSAS-II] Help with refining instrumental parameters
Message-ID:
        <CA+xw77uW_ZF-7N3f4UU7kiZFQ-vh42VkZ3MsAXPGj04BM4g=7w at mail.gmail.com <mailto:7w at mail.gmail.com> >
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 In GSAS I when there was more than one phase you could refine GU GV, GW
and LX, LY for each
phase separately. Is that possible in GSAS II? If so how?

Sorry if you have received this message multiple times - I have been having
trouble with the server.


Thank you for your help!

    Best Regards,
    Emily Siska


-- 
Emily Siska

Chemistry Graduate Assistant
Chemistry/HiPSEC

Science and Engineering Building, Room 2173
University of Nevada, Las Vegas
4505 S. Maryland Pkwy.
Las Vegas, NV 89154-4003
Office: (702) 894-1478
Cell: (818) 642-7718
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Message: 2
Date: Wed, 22 Aug 2018 11:16:49 -0700
From: Sergey Ushakov <svushakov at ucdavis.edu <mailto:svushakov at ucdavis.edu> >
To: gsas-ii at aps.anl.gov <mailto:gsas-ii at aps.anl.gov> 
Subject: Re: [GSAS-II] Help with refining instrumental parameters
Message-ID:
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In GSAS-2 you refine size and strain for each phase instead. It makes sense
since instrument parameters do not vary with phase!

On Wed, Aug 22, 2018 at 10:58 AM, Emily Siska <siskae at unlv.nevada.edu <mailto:siskae at unlv.nevada.edu> >
wrote:

> In GSAS I when there was more than one phase you could refine GU GV, GW
> and LX, LY for each
> phase separately. Is that possible in GSAS II? If so how?
>
> Sorry if you have received this message multiple times - I have been
> having trouble with the server.
>
>
> Thank you for your help!
>
>     Best Regards,
>     Emily Siska
>
>
> --
> Emily Siska
>
> Chemistry Graduate Assistant
> Chemistry/HiPSEC
>
> Science and Engineering Building, Room 2173
> University of Nevada, Las Vegas
> 4505 S. Maryland Pkwy.
> Las Vegas, NV 89154-4003
> Office: (702) 894-1478
> Cell: (818) 642-7718
>
> _______________________________________________
> GSAS-II mailing list
> GSAS-II at aps.anl.gov <mailto:GSAS-II at aps.anl.gov> 
> https://mailman.aps.anl.gov/mailman/listinfo/gsas-ii
>



-- 
--
Sergey Ushakov PhD

Staff Research Associate

Peter A Rock Thermochemistry Laboratory and NEAT ORU
Rm 4415, Chemistry Annex
University of California, Davis
Davis, CA 95616
phone (530) 902-8185
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