How much mismatch? If you're getting a good profile fit, I'd be inclined
to doubt that it is a consequence of preferred orientation. You could mix
your sample with another material (corundum powder, cork) to try to reduce
the degree of preferred orientation, and see if that makes a difference.
...@stonybrook.edu
Para: Breogan Pato Doldan breogan.p...@udc.es, rietveld_l@ill.fr
Rietveld_L@ill.fr
Enviados: Miércoles, 5 de Febrero 2014 11:55:59
Asunto: Re: Preferred orientation and lattice parameters
How much mismatch? If you're getting a good profile fit, I'd be inclined to
doubt
Hi! Be careful with LeBail. There is a paper (I can send it to you)
showing, that this method may give some errors (so is probably also for
Pawley method).
Best regards!
Btw: preferred orientation should not influence the c parameter, but the
intensity of an reflection. It can be influenced by
...@stonybrook.edu
*Para: *Breogan Pato Doldan breogan.p...@udc.es,
rietveld_l@ill.fr Rietveld_L@ill.fr
*Enviados: *Miércoles, 5 de Febrero 2014 11:55:59
*Asunto: *Re: Preferred orientation and lattice parameters
How much mismatch? If you're getting a good profile fit, I'd be
inclined to doubt
: Thursday, 6 February 2014 5:25 PM
To: Breogan Pato Doldan; rietveld_l@ill.fr
Subject: Re: Preferred orientation and lattice parameters
Dear Breogan,
just three small additions:
(i) .25 Å is a lot, if the lattice parameter in that direction is 4 Å, but much
less if it is 40 Å
(ii) Definitely
Dear Ross,
I presume on the flat sample you measured regular theta-2theta diagrams,
then only probed those planes parallel to the sample plane. In such a
situation, you do not probe correctly the texture, and all the models
you could envisage are just giving back parameters that have been
and doing the maintenance on two others so no time today
for any jousting by email.
Pam
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Sent: May 18, 2008 7:44 PM
To: Whitfield, Pamela; [EMAIL PROTECTED]
Cc: rietveld_l@ill.fr
Subject: RE: Preferred orientation
To: Whitfield, Pamela
Subject: RE: Preferred orientation?
Well said, Pamela! Come to St. Louis and I'll buy you a Budweiser!
By the way, do you know of any need for an old Scintag/Seifert
diffractometer - just the theta and 2-theta box? It's vintage 1982 or
so from a horizontal diffractometer
From a theoretical point of view, preferred orientation
means orientational texture. There may be size textures,
strain textures, grain boundary textures, dislocation textures
etc. as well, although seldom in practical use. Therefrom, in
practical use, texture is meant orientational texture
From a theoretical point of view, preferred orientation
means orientational texture. There may be size textures,
strain textures, grain boundary textures, dislocation textures
etc. as well, although seldom in practical use. Therefrom, in
practical use, texture is meant orientational texture and
Dear all,
If, I can to obtain the data from Bragg-Brentano geometry, obtained by very
slowly steps (maybe to 20-30 seconds), Can I make a microstructure analysis
(crystalline sizes and residual tensions) using Rietveld refinament?
Best regards,
Mario Macias
UIS, Colombia
_
From: Whitfield, Pamela [mailto:[EMAIL PROTECTED]
The texture versus preferred orientation difference has some signficant
blurry edges from a practical point of view.
If you want it, it's texture. If you don't want it, it's preferred
orientation!
Matthew
The texture versus preferred orientation difference has some
signficant blurry edges from a practical point of view.
If you want it, it's texture. If you don't want it, it's preferred
orientation!
The discussion seems not for a nervous.
A naive question of a baby watching adults in the
If you want it, it's texture. If you don't want it, it's preferred
orientation!
Preferred orientation is what you get with X-rays; neutrons are good for
measuring texture :-)
Seriously, texture is a term best applied to solid materials, where
crystallites have preferred orientation due to the
In fact I think you might find it helps quite a bit. Have a look at:
http://img.chem.ucl.ac.uk/www/vickers/po/po.htm
Martin
Subject: RE: Preferred orientation?Date: Thu, 8 May 2008 10:55:12 -0400From:
[EMAIL PROTECTED]: rietveld_l@ill.fr
I do that myself but it doesn’t always help
://pd.chem.ucl.ac.uk/pdnn/inst1/texture1.htmhttp://pd.chem.ucl.ac.uk/pdnn/inst1/texture2.htm
PPS for anyone interested in the TV ad that came to mind during this
discussion, see:
http://www.nationalarchives.gov.uk/films/1964to1979/filmpage_lonely.htmMartin
Subject: RE: Preferred orientation?Date
Martin wrote:
PS For anyone interested in an explanation of texture vs. PO, see:
http://pd.chem.ucl.ac.uk/pdnn/inst1/texture1.htm
http://pd.chem.ucl.ac.uk/pdnn/inst1/texture2.htm
I disagree! The web page has confused texture with granularity. See:
Luca,
I understood Gerard's problem to have a measurement of a powder (of
unknown particle shape) in Bragg-Brentano geometry, for structure
refinement. As you said the graininess problem can be minimized
primarily by grinding and to a certain extent by rotation and enhancing
the divergence,
Dear Reinhard,
If I want make a microstructure analysis of data from Bragg-Brentano scan.
Can I use spherical harmonic model and Rietveld refinament content into
Fullprof?
Best regars,
Mario Macias
UIS, Colombia.
Luca,
I understood Gerard's problem to have a measurement of a powder (of
On May 8, 2008, at 12:30 AM, May, Frank wrote:
You can check for texture effects (preferred orientation) by
obtaining multiple patterns of the material. It's realistic to
expect some differences, but preferred orientation is manifest by
not being able to replicate the pattern.
Not
Luca,
speaking about powder samples, Frank is right. The PO of powder mounts
is seldom reproducible and the filling technique is responsible for
particle orientation, depending on particle shape, filling direction,
pressure... In practice it is a nice trick to repeat the filling of the
powder
Another way to check or convince yourself of preferred orientation is to
take note what is happening when grinding the sample.
Some crystallite samples will fracture along a particular plane upon
grinding and this summed up for the whole sample may produce preferred
orientation. Alternatively,
-Original Message-
From: William Bisson [mailto:[EMAIL PROTECTED]
Sent: May 8, 2008 9:29 AM
To: rietveld_l@ill.fr
Subject: Re: Preferred orientation?
Another way to check or convince yourself of preferred orientation is to
take note what is happening when grinding the sample.
Some
Forget all that long winded stuff. Just collect the data on capillary
transmission geometry and avoid all (well, most of) the fuss.
Martin Vickers
_
Be a Hero and Win with Iron Man
I do that myself but it doesn't always help much if you've got something
like wollastonite! J
From: Martin [mailto:[EMAIL PROTECTED]
Sent: May 8, 2008 10:51 AM
To: rietveld_l@ill.fr
Subject: RE: Preferred orientation?
Forget all that long winded stuff. Just collect the data on capillary
, 2008 9:16 AM
To: Kurt Leinenweber
Subject: RE: Preferred orientation?
It's one of the classic needle-shaped materials - it gives lovely SEM
images if you can avoid charging
From: Kurt Leinenweber [mailto:[EMAIL PROTECTED]
Sent: May 8, 2008 12:12 PM
To: Whitfield, Pamela
Subject: RE: Preferred
Leinenweber [mailto:[EMAIL PROTECTED]
Sent: Thursday, May 08, 2008 12:37 PM
To: rietveld_l@ill.fr
Subject: RE: Preferred orientation?
Hi all,
This thread gives me a chance to ask a question I've had for a long time.
I've heard about these large chambers where you can mix your sample with a
binder
Reinhard,
I stick with what Gerard said:
But i have no other information that supports the existence of
preferred orientation
so what information give you the confirmation it is the powder mount
responsible of preferred orientation. I work almost exclusively with
image plate detectors
visitors to my lab must sometimes think I'm very vain!
Pam
From: Peter Y. Zavalij [mailto:[EMAIL PROTECTED]
Sent: May 8, 2008 12:48 PM
To: 'Kurt Leinenweber'
Cc: rietveld_l@ill.fr
Subject: RE: Preferred orientation?
Kurt,
An old way used for alloys is:
grease the surface
:Re: Preferred orientation?
To: [EMAIL PROTECTED]
Copies to: rietveld_l@ill.fr
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Reinhard,
I stick with what Gerard said:
But i have no other information that supports the existence
Dear Gerard,
The low-angle intensity problem might come from disordered
regions, like water or solvent molecules occupying some voids.
Also, poor modeling of weakly scattering atoms, like hydrogen,
may lead to the similar problem.
Best regards,
Yaroslav
http://filinchuk.com
You can check for texture effects (preferred orientation) by obtaining multiple
patterns of the material. It's realistic to expect some differences, but
preferred orientation is manifest by not being able to replicate the pattern.
That's the simple test. Let us know what you find.
Another
At 12:04 19/01/99 +0100, Lubo wrote:
Hi Armel,
I am sure you will not be satisfied by this answer, but my solution to
this problem is : USE transmission geometry. We have been doing it for
years getting nice results for kaolinites, micas, vermiculites and
smectites, not to
speak of some organic
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