[Ifeffit] Missing ipot problem

Bruce Ravel ravel at phys.washington.edu
Sat Jul 9 15:28:24 CDT 2005

On Monday 04 July 2005 18:57, rvv052 at mail.usask.ca wrote:
> I was able to fix the problem with too many atoms, but then I get another
> error. It says: No atoms or overlap cards for unique pot 1  Cannot
> calculate potentials, etc. I know that this problem occurs because
> potentials 0, 2, 3, 4, 5, and 7 exist in the ipot coloumn, but I do not
> have a 1 potential (or a 6 potential as I found out by assigning a 1
> potential to one of the other atoms). I never encountered this problem with
> ifeffit during my other calculations, so I am wondering what it means and
> what I can do about it.


Feff is not so clever about how it handles the ipots.  There are hard rules 
that you have to follow.

1.  Every ipot defined in the potentials list has to be present in the atoms 

2.  The central atom must be ipot 0

3.  There can only be 7 ipots other than the central atom, for a total of 8 
unique potentials.  (i.e. the largest ipot is 7)

4.  You cannot skip any ipots.  If you only have three kinds of atoms (other 
than the absorber, they must be 1, 2, and 3).

It would seem the solution to your problem is to observe #4.  Reading the 
documentation is sometimes useful.  Most of the rules are explained at

 Bruce Ravel  ----------------------------------- bravel at anl.gov  -or-
                                                  ravel at phys.washington.edu
 Environmental Research Division, Bldg 203, Room E165
 Argonne National Laboratory                        phone: (1) 630 252 5033
 Argonne IL 60439, USA                                fax: (1) 630 252 9793

 My homepage:    http://feff.phys.washington.edu/~ravel 
 EXAFS software: http://feff.phys.washington.edu/~ravel/software/exafs/

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