[Pw_forum] scf stops after finishing 100 iteration

[Stefano de Gironcoli]

have you verified that your crystal structure is reasonable using a 
visualizer like xcrysden or similar ?
it appears to me that a couple of atoms are very very close to each other.
stefano

Dimpy Sharma wrote:
>
> Hi Quantum espresso users,
>
> I tired to perform scf calculation but it shows me the following error
>      'convergence NOT achieved after 100 iterations: stopping'
>
> However the nscf calculation and projected density of states run 
> successfully, why is this so?
>
> My input file is as follows
>
> &CONTROL
>      calculation ='scf'
>     restart_mode = 'from_scratch'
>           outdir = '/sfiwork/dsharma/PDOSSilane/PDOSsi/si_wfc'
>       pseudo_dir = '/sfiwork/dsharma/QE_Pseudos/'
>           prefix = 'si'
>          tstress = .true.
>          tprnfor = .true.
>    etot_conv_thr = 1.D-4
>    forc_conv_thr = 1.D-3
>            nstep = 600
>           wf_collect =.true.
>  /
>  &SYSTEM
>         ibrav = 0
>     celldm(1) =7.4088
>           nat = 6
>          ntyp = 1
>       ecutwfc = 40
>       ecutrho = 160.0
>          nbnd = 12
>  /
>  &ELECTRONS
>     diagonalization ='david'
>         mixing_mode = 'plain'
>            conv_thr = 1.0d-6
>         mixing_beta = 0.7
> /
> &IONS
>  /
> &CELL
>  cell_dynamics='none'
>  /
> CELL_PARAMETERS cubic
>      1.000000000    0.000000000    0.000000000
>      0.000000000    2.000000000    0.000000000
>      0.000000000    0.000000000    2.000000000
> ATOMIC_SPECIES
>    Si   28.08600  Si.pz-vbc.UPF
> ATOMIC_POSITIONS angstroms
>  Si        2.95020       -0.66592       -0.12341
>  Si        4.90939        0.61749        0.11358
>  Si        0.99475        0.65272       -0.16138
>  Si       -0.98472       -0.62740       -0.15123
>  Si       -2.94624        0.68229       -0.12124
>  Si       -4.89549       -0.61534        0.11905
>  K_POINTS automatic
>   4 1 1   0 0 0
>
> Can anybody give me any suggestions?
>
> Thanks
>
> Dimpy
>
> Dimpy Sharma,
> PhD
> Electronics Theory  Group
> UCC,Cork
> Ireland
>
>
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