Pamela,
At 10:24 07.06.2004 -0400, you wrote:
>In a perfect world this would be the case, but given that very few people
>run systems that conform to the requirements for true fundamental parameters
>(Bragg-Brentano with NO monochromator, mirrors, etc), then one is not really
>using fundamental par
Riza (& other newbies),
I personally recommend starting with the web tutorial on alumina
(http://www.ncnr.nist.gov/programs/crystallography/software/expgui/tutorial3/index.html).
There is a reason why the GSAS manual starts with a "simple" TOF
refinement, but it is not where I would recommend st
Dear Arie and others
What you have described is the classic "dominant zone" pathology, which I
described in 1975 at the Amsterdam Congress and many times subsequently.
The problem (and opportunity) here is that two of the reciprocal lattice
vectors (let's call them and ) and hence the associat
One of the problems is that the 'apparent sizes' don't correspond to
physical dimensions at all. They correspond to what is known as an average
column length. If you imagine a crystallite cut into rectangular strips (or
a series of stacked unit cells), these are the columns. A simple analogy
wou
Dear Dr Pamela Whitfield ,
Thank you very much for your detail replies on this particular topic.Yours replies
were quite benificial for me.
Please write something about what do (physically) volume weighted and area weighted
domain size mean.
Thanking you.
Regards,
Apu
*
Domain size work is a bit of a can of worms. It's something I looked at
more carefully a while back for nanoparticle work, and the deeper I got into
it the worse it got.
Peak broadening methods tend to give 'apparent' sizes, either area or volume
weighted, and require corrections (usually not don
Dear All,
Following the discussion about fundamental parameters
approach (which was very helpful), I have a few more
questions regarding the profile functions and their
refining. I apologise if they seem very trivial (or
plain stupid).
We have a Philips PW3040 X'celerator running in a flat
plate
Oooo, picking up where Friday left off..
Must go and put the coffee pot on :-)
- refining of "fundamental parameters" is nonsense, unless one is not
familiar with his diffractometer or want/must "absorb" any unkown effects
or weaknesses of his model :-)
In a perfect world this would be the c
Hi Jon and Pamela,
my very personal opinion regarding the "fundamental parameter" stuff:
- fundamental is that the observed peak shape is a folding of contributions
from (i) wavelength distribution, (ii) instrumental/geometrical aberations
and (iii) microstructure of the sample. From this point of
>Topas will import CIF files, but the ICSD doesn't always
>export CIF files in the same format as Topas is expecting.
Is the problem with Topaz or with ICSD ? I would be interested in fixing examples of
incorrect CIF files exported by http://icsd.ill.fr/
Alan.
Alan Hewat, ILL Grenoble, FRANCE
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