Hi Nic,
On Aug 2, 2011, at 6:41 AM, nicholas@csiro.au wrote:
Just a sidenote, is the general workflow for fitting XAFS data the
following:
Fit first shell and get reasonable Enot and Amp and then make set
them, then incrementally add more of the scatter paths and adjust
the delR for
Nic,
I think that you have rediscovered something many of us have found before you.
If your fit is wonky -- an E0 of >50 for instance -- that usually means you
have made a mistake in your starting structure.
In this case, there was a problem in the crystal data. Sonetimes one presumes,
say, a
these type of
analysis.
Many thanks,
Nic
-Original Message-
From: ifeffit-boun...@millenia.cars.aps.anl.gov
[mailto:ifeffit-boun...@millenia.cars.aps.anl.gov] On Behalf Of Dominik Samuelis
Sent: Tuesday, 2 August 2011 7:15 PM
To: XAFS Analysis using Ifeffit
Subject: Re: [Ifeffit] Questi
On Monday, August 01, 2011 12:36:19 am nicholas@csiro.au wrote:
> Just wondering what could I do to make the amp guess value as a positive
> number? If I run it and let it float (i.e. guess), the amp becomes
> negative in the resulting fits, but the fit has nice delr and ss values
> (i.e. make
Dear Nic,
this sounds like your fit is shifted to the experimental chi(k) by half
an oscillation period. Typically, you can recognize this by looking at
the enot value. So what is your enot value like? Does it help changing
the enot starting value by a couple of eV? Finally, (and this is a FAQ
Hi Nic,
The delr and ss values may adopt reasonable values with a negative
amp, but they're almost certainly not the right values. A negative amp
turns the chi(k) upside-down. To make it ft, the other parameters then
have to shift the graph over by half an oscillation, yielding values
of
Dear All,
Just wondering what could I do to make the amp guess value as a positive
number? If I run it and let it float (i.e. guess), the amp becomes negative in
the resulting fits, but the fit has nice delr and ss values (i.e. make sense).
If I restrict the amp value to 1, everything else does
