[Pw_forum] how to make scf converged for a (3,0) CNT?

[lan haiping]

Hi,
CNT (3,0) should be a metallic system, therefore, you need specify the
smearing scheme for it.

And , please supply your affiliation.

regards

On Mon, Nov 2, 2009 at 9:54 AM, Zhu Xi <ustc0200 at gmail.com> wrote:

> Hi PW users,
> I can't make the scf converged for a (3.0) CNT, can anyone give some
> advice? Thanks!
>
> the input is
> ++++++++++++++++++++++++++++++++++++++++++
> &control
>          calculation='relax',
>          PSEUDO_DIR='./',
>           restart_mode='from_scratch',
>          prefix='cnt30',
>          forc_conv_thr=1.0D-4,
>          outdir='./' ,
>           wf_collect=.true. ,
>         /
> &SYSTEM
>          ibrav = 0,
>          celldm(1)=0,
>          nat = 12,
>          ntyp = 1,
>          ecutwfc = 30.0 ,
>          ecutrho = 300,
>          nbnd = 30,
> /
> &electrons
>         conv_thr    = 1.D-6,
>         mixing_beta = 0.2,
> /
> &IONS
>  ion_dynamics = 'damp'
> /
> CELL_PARAMETERS
> 8.0502333261  0.0  0.0
>  0.0 18.897261329  0.0
>  0.0  0.0 18.897261329
> ATOMIC_SPECIES
>     C    12.00000 C.pz-rrkjus.UPF
> ATOMIC_POSITIONS (crystal)
> C   0.8333333333333349   0.5587165273624200   0.3982999913642820
> C   0.3333333333333350   0.4412834726375799   0.6017000086357180
> C   0.6666666666666640   0.4412834726375799   0.3982999913642820
> C   0.3333333333333350   0.4412834726375799   0.3982999913642820
> C   0.6666666666666640   0.4412834726375799   0.6017000086357180
> C   0.8333333333333349   0.5587165273624200   0.6017000086357180
> C   0.6666666666666640   0.6174330547248399   0.4999999999999999
> C   0.3333333333333350   0.6174330547248399   0.4999999999999999
> C   0.8333333333333349   0.3825669452751600   0.4999999999999999
> C   0.1666666666666630   0.5587165273624200   0.6017000086357180
> C   0.1666666666666630   0.5587165273624200   0.3982999913642820
> C   0.1666666666666640   0.3825669452751600   0.4999999999999999
> K_POINTS {automatic}
> 21 1 1 0 0 0
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
>
>
>
> the out put is
> ============================================================
>      ethr =  1.21E-06,  avg # of iterations =  1.0
>
>      negative rho (up, down):  0.642E-04 0.000E+00
>
>      total cpu time spent up to now is      0.62 secs
>
>      total energy              =  -135.75618000 Ry
>      Harris-Foulkes estimate   =  -135.75624906 Ry
>      estimated scf accuracy    <     0.01236748 Ry
>
>      End of self-consistent calculation
>
>      convergence NOT achieved, stopping
>
>      Writing output data file cnt30.save
>
>      PWSCF        :  0m 0.62s CPU time,    57m23.48s wall time
>
>      init_run     :     0.00s CPU
>      electrons    :     0.62s CPU
> =================================================================
>
>
> compiler flag is -O2 -axW by ifort10.1015 and mpich2.1.08
>
>
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>


-- 
Hai-Ping Lan
Department of Electronics ,
Peking University , Bejing, 100871
lanhaiping at gmail.com, hplan at pku.edu.cn
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