[Pw_forum] problem with vc-relax

[Phillip Nyawere]

Try cell_dynamics='bfgs' and not 'damp'
Success

On Tue, Jul 27, 2010 at 12:42 PM, Olga Sedelnikova
<o.sedelnikova at gmail.com>wrote:

> Dear All,
> I have a problem with 'vc-relax' option for graphene. I have used david
> and cg diagonalization proceedures, different types of smearing and ion and
> cell dynamics but all calculations were crashed.
> One of my input file:
>
> &CONTROL
>      calculation = 'vc-relax',
>      prefix = 'graphene',
>      restart_mode='from_scratch'
>      tstress=.true.,
>      tprnfor=.true.,
>      nstep=45,
>       etot_conv_thr = 1.0E-4 ,
>       forc_conv_thr = 1.0D-3 ,
>       max_seconds = 36000 ,
>       dt = 100,
>    /
> &SYSTEM
>      ibrav = 4,
>      celldm(1)= 4.64833
>      celldm(3)=5.447621
>                nat = 2,
>                ntyp = 1,
>                ecutwfc = 18.0,
>                nbnd =8,
>      occupations='smearing'
>      smearing = 'mv'
>      degauss = 0.005
>        /
> &ELECTRONS
>      conv_thr = 1.0d-7
>      electron_maxstep = 70
>      diagonalization='cg'
>    /
> &IONS
>      ion_dynamics='damp'
> /
> &CELL
>     cell_dynamics = 'damp-w' ,
>     press=0.00 ,
>     wmass=0.0015 ,
> /
>
> ATOMIC_SPECIES
>      C   12.01100 C.pz-vbc.UPF
> ATOMIC_POSITIONS crystal
>     C      0.00000000    0.00000000    0.50000000
>     C      0.33333333    0.66666666    0.50000000
> K_POINTS {automatic}
>    6 6 6 0 0 0
> Inthis cause:
>
> from electrons : error #         1
>      charge is wrong
> Maybe somebody has already dealed with this problem and can advice the
> correct options for graphene.
> Any suggestion will be appreciated.
>
> --
> Best wishes,
> Olga Sedelnikova
> Nikolaev Institute of Inorganic Chemistry of SB RAS
>
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>


-- 
Phillip W. Otieno Nyawere,
Kabarak University,
Dept of Physics & Mathematics,
P.O Box Private Bag - 20157,
Kabarak, Kenya.
Tel +254728342054
pnyawere at gmail.com, potieno at kabarak.ac.ke

The battle belongs to the Lord.
CURRENTLY IN CAPE TOWN, SOUTH AFRICA
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