[Ifeffit] Problem with creation of feff paths for americium in artemis

[Bruce Ravel]

Hi Daniel

> We are looking forward to a beamtime investigating americium complexes and
> I wanted to create feff-paths for americium sulfate by using
> crystallographic data of europium sulfate and replacing Eu by Am. Atoms
> runs well and creates the feff.inp but when I then try tu run Feff I just
> get the error message
> 
>  Feff 6L.02
>  ?
>  Eu H4 N O8 S2
>  Ruiz-Valero, Caridad
>  New catalytically active neodymium sulfate
>  Calculating potentials and phases...
>      free atom potential and density for atom type    0
>   cannot remove an electron from this level
>  Fatal Error: at GETORB-1
> 
> Their seems to be a problem with the atomic number because if I change Z=95
> to 94 it runs without any problem. Is it possible to run it anyway with
> Z=95 or must I go for 94 instead which is the atomic number of Pu?

I took a quick look at the feff6 source code (line 271 and following
at https://github.com/newville/ifeffit/blob/master/src/feff6/getorb.f).
I don't see how Americium could ever work in Feff6.  The error you
mention seems guaranteed to be generated unless you do
something unusual with the feff.inp file.

It does seem like the problem would go away for Am if you defined Cm
in getorb.f and recompiled Feff.  I understand that might be a tall
order -- it's just a suggestion ...

I have never needed to look at Am -- does anyone else here have any
experience with feff6 and Am?

Seems to me that you have two options, (1) use Pu as the central atom,
at least so you have something to start with, (2) try a more
recent -- but not free and not distributed with Ifeffit -- version of
Feff.  I don't know one way or the other if later versions of Feff
handle atoms above Pu any differently.


> Furthermore, I wanted to calculate the potentials with SCF approach but I
> read a lot of "google search results" without finding any helpful
> information.Or isn't it needed at all...?

Feff6 does not do self-consistency.  That was introduced in Feff8.
Ifeffit ships with the free version of Feff6.  If you look through the
archives of this mailing list, you will see discussion of using later
versions of Feff in place of Feff6 with Artemis.

B




-- 

 Bruce Ravel  ------------------------------------ bravel at bnl.gov

 National Institute of Standards and Technology
 Synchrotron Methods Group at NSLS --- Beamlines U7A, X24A, X23A2
 Building 535A
 Upton NY, 11973

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