[Ifeffit] Generating single scattering paths in Artemis

Carlo U. Segre segre at iit.edu
Thu Jan 6 23:21:41 CST 2005


You asked for implementation ideas and so are some thoughts.

First of all, I really like the Artemis interface.  While it is complex, 
it needs to be to actually make it useful for complex analysis projects.

I like the idea of selecting "Single scattering cluster" and then getting 
a left hand window with a tab labeled "Cluster" and one labeled 
"Interpretation".  I agree that there is no need for a "feff.inp" tab here 
because the power user will just use one of the other ways proposed in 
this thread to generate paths the way they want them.

Now, how to best build a cluster.  Selecting the absorber and scatterer 
could be drop down lists as could be the absorbing edge.  The distance 
could be an input box and the coordination would be a drop-down list with 
common coordination types single (1 atom only), linear (2 atoms in linear 
arrangement), tetrahedral, octahedral and icosahedral.  If there is a 
desire, one could even offer the complete IUPAC list


but this probably would be overkill, a simple subset should do.

There could be a drop down list of standard coordinations from a database 
that, when selected, would just fill in the boxes appropriately.

At the bottom, I would put a big FEFF button and then allow the user to 
proceed with analysis just like as the current system.


On Thu, 6 Jan 2005, Bruce Ravel wrote:

> The solution I see is a combination of Sam's periodic table thing and
> the solution I suggested two emails ago.  It could work something like
> this:
>  a. Choose "Single scattering fit" from one of the menus
>  b. Pop up a dialog in which the user tells Artemis:
>       i.   the species of the absorber
>       ii.  the species of the scatterer
>       iii. the approximate distance to the first shell
>       iv.  the geometry
>  c. Artemis constructs a suitable feff.inp file, runs Feff without
>     asking for confirmation, and imports only the first path
>  d. Variables for amplitude, sigma^2, delr, and e0 are generated
>     automatically, just like they are now
>  e. Artemis pops up a dialog asking the user if she wants to run the
>     fit immediately or later.  The immediate choice is just like the
>     big green button, the later choice lets the user examine things
>     before pressing the big green button.
> A few comments:
> Regarding step b.i. and b.ii.: This could be a periodic table, like
>  Sam uses or a couple of entry boxes, which would be more compact
> Regarding step b.iv.: I think I would include some real diatomic
>  crystal structures, such as rock salt, cesium chloride, zinc
>  sulfide, along with the things in Sam's list (square planar,
>  octahedral, tetrahedral, according to the screenshot on his web
>  site)
> This approach is simpler than how Artemis currently works only in that
> it automatically jumps through several steps without stopping.  Once
> the fit is done, the user is still looking at Artemis and Artemis is
> just as complicated as it ever was.
> However, the advantage of this approach over, say the overlap thingie,
> is that one is in a position to begin using some of Artemis' tools to
> look beyond a simple first shell fit.
> In short, the bad news is that it is still Artemis, but the good news
> is that it is still Artemis.
> Like Scott, we all vote that Artemis work better.  But Artemis is the
> product of a benevolent dictatorship rather than of a democracy.
> While you all are welcome to cast a vote for the goodness of Artemis,
> I'm really looking for concrete design suggestions.
> B

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

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