icol...@grace.com
-Original Message-
From: Alan Hewat [mailto:he...@ill.fr]
Sent: Wednesday, February 10, 2010 5:43 AM
To: Jacco van de Streek
Cc: rietveld_l@ill.fr; alan.he...@neutronoptics.com
Subject: Re: Negative Biso / absorption in TOPAS.
> 1. Is absorption indeed the most likely c
> 1. Is absorption indeed the most likely cause of this problem or are
> there other possibilities?
>
> 2. How do we model absorption in TOPAS? Which keyword do we use and what
> are reasonable values for the parameters in the expression?
1. You will find discussions of negative B-factors in the R
Lubomir Smrcok wrote:
> could you kindly tell us the composition of the sample and the technique
> used to collect the data ?
The technique to collect the data is unfortunately not known to me, I'd
have to ask.
The composition is not a secret: it is an organic pigment, Pigment
Yellow 110, and its
Jacco,
could you kindly tell us the composition of the sample and the technique
used to collect the data ?
Lubo
On Wed, 10 Feb 2010, Jacco van de Streek wrote:
Dear colleagues,
I am helping some people from the University of Frankfurt with their
Rietveld refinements, and usually their powde
Dear colleagues,
I am helping some people from the University of Frankfurt with their
Rietveld refinements, and usually their powder patterns are measured on
their own instrument and the refinements are excellent. This time,
however, they have to work with a powder pattern that was sent to them.
I
Quoting Alan Hewat <[EMAIL PROTECTED]>:
> > There were discussions about the factors that may cause negative atomic
> > displacement parameters for XRD data. What about neuton data and how to
> > solve the problem (time-of-flight data in this case) ?
>
> Negative temperature factors Biso mean tha
> There were discussions about the factors that may cause negative atomic
> displacement parameters for XRD data. What about neuton data and how to
> solve the problem (time-of-flight data in this case) ?
Negative temperature factors Biso mean that low d-spacing (high-Q :-))
peaks are stronger tha
Hello,
There were discussions about the factors that may cause negative atomic displacement parameters for XRD data. What about neuton data and how to solve the problem (time-of-flight data in this case) ?
Thanks,
Henry
Dear All,
I'm currently doing refinement for a Cs-Zr-Si-O phase using GSAS. While
the refinement proceeded stably and the final cycle got converged, the
displacement factors (Biso) were negative except for Cs. I tried with two
sets of data collected on two diffractometers, and the situations are
