[Wien] SCF with force convergence

[Nandan Tandon]

Dear Stefaan,

Can you please eleborate

"there are no atoms with a free parameter in their coordinates"

I dont understand what the free parameters are? For instance i am working 
with Wurtzite GaN doped system wherein i am not able to get 
convergence of 5 mRy/a.u. We have used the experimental lattice constant 
and formed the unit cell from which a supercell was generated.

I did try to look up the archives but could not find an answer.

Regards,

Nandan.


On Fri, 6 May 2005, Stefaan Cottenier wrote:

>
>> When I run SCF with the option force convergence I get an error message 
>> "Force convergence not possible. Forces not present". With other (charge & 
>> energy) options SCF works okay.
>> Could you suggest where I might have gone wrong?
>
> You are probably using a structure where there are no atoms with a free 
> parameter in their coordinates (like bcc-Fe, or TiC). There no forces in such 
> case, and force convergence as criterium is not applicable.
>
> Stefaan
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Nandan Tandon
Research Student
Department of Physics,
University of Pune
Pune-411007                             Tel.(O)+91-20-25692678 ext 426
MAHARASHTRA, INDIA.                     Fax.(O)+91-20-25691684 
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