[Pw_forum] (no subject)

[Tone Kokalj]

On Sat, Jul 24, 2004 at 09:11:54PM +0530, Raghani Pushpa wrote:
> dear users,
> i was doing the slab calculations and wanted to fix some of the middle
> layers, so at the end of the atomic positions i gave "iforce(i=1-3)=0".
> but in the output the warning comes as "Warning: card   IFORCE(I=1-4)=0
> ignored". what does this warning mean? and is the code going to keep the
> last three atoms fixed?
>
> ATOMIC_POSITIONS
> Cu   0.0      0.0       2.09431
> Cu   0.       0.577350 -2.09431
> Ru   0.5      0.288675  1.25659
> Ru   0.       0.577350  0.418863
> Ru   0.       0.0      -0.418863
> Ru   0.5      0.288675 -1.25659
>   iforce(i=1-3)=0

No it will not, as the "iforce" line will be ignored. Instead, you
should use

ATOMIC_POSITIONS
Cu   0.0      0.0       2.09431
Cu   0.       0.577350 -2.09431
Ru   0.5      0.288675  1.25659
Ru   0.       0.577350  0.418863  0 0 0
Ru   0.       0.0      -0.418863  0 0 0
Ru   0.5      0.288675 -1.25659   0 0 0	

In the last three lines the zeros at 5th/6th/7th column mean:
"don't move this atom in x/y/z direction".

Regards, Tone

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| Anton Kokalj                                 Email: Tone.Kokalj at ijs.si |
| Department of Physical and Organic Chemistry Phone: x 386 1 477 3523   |
| Jozef Stefan Institute                         Fax: x 386 1 477 3811   |
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