[Pw_forum] How to do the relaxation calculation by keeping one atom at a fixed coordinate???

[Stefano Baroni]

You have to do nothing. Just relax the structure, and translate the  
relaxed structure so as the new position of the first atom coincides  
with the old one. Because of translational invariance, the position  
of any individual atom is arbitrary. SB

On Apr 5, 2007, at 11:43 AM, pnspeaks at sify.com wrote:

> Hi,
>
>      I want to do a relaxation calculation of a 32
>
>   atom
> cell by keeping one atom at a fixed position and other 31 atoms to
> be
> relaxed.Is it possible to do the problem by setting
> X-iforce,Y-iforce and
> Z-iforce equals to 1 for 31 atoms and by not
> setting for the atom I want to be
> fixed ? Or, there is some other
> procedures for doing the job? Please help.
>
>
>
>
>
>   Prithwish
> Nandi
>
>   Research Scholar
>
>   IGCAR, Kalpakkam, India
>
>
>
>
>
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---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
Trieste
[+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)

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