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["Anglade Pierre-Matthieu" <anglade@gmail.com>]

Hi John,

I'm not sure about the following answer but :
1) are you sure your computation is converged in term of
-ecut (looks very small for something with O and V)
-kpt (looks to much homogeneous for your cell)
-number of bands
2) are you sure that your scf cycles are converging during your
geometry optimisation ?
3) are you sure your large forces are not coming from the fact you
have fixed some coordinates in your cell ? Doing this will probably
make abinit consider the forces on the fixed atoms along the fixed
axis as zero. Don't you think so ? Can't it be the reasons of your
problem ?

Best regards

PMA

On 10/27/06, john Bob <bobjohn.lzu@gmail.com> wrote:
> Dear Abinit Users:
>          I have done the acell optimization,and it was converged.But
> when I use the converged acell to do another scf calculation ,I find
> the cartesian force is much larger than the converged tolmxf.
>          Is anything wrong with my configure file ,what's the
> difference  between the two cartesian forces?
>         Any advise is appreciated.
>
>
> =======================================
> v2o5.in:
>
> acell 21.75453 6.73498 8.25432
> rprim
>     1.000000  0.000000  0.000000
>     0.000000  1.000000  0.000000
>     0.000000  0.000000  1.000000
>
> #Definition of the atom types
> #      14 kind of atoms
> #       ['O', 'V']
> ntypat 2
> znucl  8 23
>
> #Definition of tha atoms
> natom  14
> typat  1 1 1 1 1 1 1 1 1 1 2 2 2 2
>
> xred
>  1.1769520088E-01  2.5000000000E-01  4.5665597737E-01
>  3.8230479912E-01  2.5000000000E-01  4.5665597737E-01
>  8.8230479912E-01  7.5000000000E-01  5.4334402263E-01
> .....
>
> natfixy 14
> iatfixy 1 2 3 4 5 6 7 8 9 10 11 12 13 14
>
> # Kpoints
> kptopt 1
> #ngkpt 4 4 4
> ngkpt 3 3 3
>
> getwfk -1
>
> ecut 10
>
> nstep 100
> toldfe 1.0d-6
>
> diemac 8.0
>
> optcell 1
> tolmxf 1.0d-4
>
> ionmov 3
> ntime 100
> dilatmx 1.1
> ecutsm 0.5
>
> #Use GGA functional
> ixc 11
>
> ===========================================================
> SCF.in
>
> acell    2.1951881203E+01  6.7960779141E+00  8.3292009550E+00 Bohr
>
> rprim
>     1.000000  0.000000  0.000000
>     0.000000  1.000000  0.000000
>     0.000000  0.000000  1.000000
>
> #Definition of the atom types
> #      14 kind of atoms
> #       ['O', 'V']
> ntypat 2
> znucl  8 23
>
> #Definition of tha atoms
> natom  14
> typat  1 1 1 1 1 1 1 1 1 1 2 2 2 2
>
> xred    1.1289399161E-01  2.5000000000E-01  4.6076081641E-01
>          3.8710600839E-01  2.5000000000E-01  4.6076081641E-01
>          8.8710600839E-01  7.5000000000E-01  5.3923918359E-01
>          ...
>
> # Kpoints
> kptopt 1
> ngkpt 3 3 3
>
>
> ecut 10
>
> nstep 100
> toldfe 1.0d-6
> #toldff 1.0d-6
>
> diemac 8.0
>
> #Use GGA functional
> ixc 11


--
Pierre-Matthieu Anglade