[Ifeffit] Generating single scattering paths in Artemis
Carlo U. Segre
segre at iit.edu
Wed Jan 5 15:43:09 CST 2005
Scott:
These are just the kind of problems I was having but I would add that for
someone who is not savvy about crystallography, having to fake a crystal
with a low symmetry space group is not terribly intuitive.
I agree with you also about the symmetry of the neighbors but, again, i
think that the benefit of an intuitive interface to what the scientist
wants to do is a good thing. I think that having to use work-arounds is
difficult to explain to new users. Perhaps a new chemistry student knows
that his/her atom has an octahedral coordination. It woujld be good to be
able to intuitively model that.
Just my $0.02
Carlo
On Wed, 5 Jan 2005 scalvin at slc.edu wrote:
> Hi Carlo,
>
> Hmmm...my initial reaction was that, rather than loading Artemis with a
> new option, it's better just to "fake it" by using a low-symmetry space
> group with a large lattice parameter and then truncating the cluster size
> at smaller than the unit cell. But I just tried this, and discovered an
> interesting problem, which you may have come across as well.
>
> What I did was attempted to create an octahedral cluster by using a space
> group of P m 3 m (simple cubic) with a=10, an Fe at 0 0 0 absorbing, and
> an oxygen at 0.2 0 0 (thus an Fe-O distance of 2 angstroms). The cluster
> size is set at 5. As expected, that generates an octahedral cluster of
> oxygens around the Fe as a FEFF.INP file. But here's the problem: Artemis
> includes a potential for scattering atoms of Fe, and there aren't any in
> the list. FEFF, in turn, doesn't like that and won't run, causing Artemis
> to give the error message:
>
--
Carlo U. Segre -- Professor of Physics
Associate Dean for Special Projects, Graduate College
Illinois Institute of Technology
Voice: 312.567.3498 Fax: 312.567.3494
Carlo.Segre at iit.edu http://www.iit.edu/~segre
More information about the Ifeffit
mailing list