[Pw_forum] self consistent calculation

[Filipe Camargo Dalmatti Alves Lima]

Dear Ahmad,

The option nbnd is related to the number of electrons that you have in your
system.
You may increase this number without increase the number of k-points.
Usually you should request nbnd equal the number of valence electrons
divided by 2 (plus more bands if you want unoccupied states, I would
suggest add +4 bands at least).

Best regards,

-- 
_________________________________________
Filipe Camargo Dalmatti Alves Lima
PhD Student
University of São Paulo, Physics Institute, Materials Physics Department,
Nanomol Group, Brazil.
Phones:    (11) 3091-6881  (USP)
                (11) 8249-4628 (TIM)



On Wed, Jul 18, 2012 at 11:41 AM, Sohail Ahmad <sohailphysics at yahoo.co.in>wrote:

> Dear Users
>
> I  run scf and nscf and calculated band structure and DOS succesfully for
> Molybdenum Disulphide (valence electron =36) in a 4x4x4 with nbnd =20
> but the problem in band structure i couldnot see sufficient no. of bands
>
> Then i tried to repeat the same in 12x12x12 with nbnd=30 but the program
> failed to run
>
> Should i try for lesser mesh for scf  and do bigger mesh for nscf ????
>
> &control
>   calculation = 'scf',
>   restart_mode = 'from_scratch',
>   prefix = 'MoSb1',
>   pseudo_dir = '/home/sandeep/espresso-4.2.1/pseudo',
>   outdir = './OUT',
>  /
>  &system
>   ibrav = 4, celldm(1) = 6.0281946, celldm(3) = 3.89, nat = 6, ntyp = 2,
>   ecutwfc = 70,
>   ecutrho = 300,
>   nbnd = 30,
>   occupations = 'smearing', smearing = 'gaussian', degauss = 0.001,
>   nspin = 2,
>   starting_magnetization(1) = 0.1d0,
>  /
>  &electrons
>   mixing_beta = 0.3,
>   conv_thr = 1.0d-9,
>  /
> ATOMIC_SPECIES
> Mo  95.96  Mo.pw91-n-van.UPF
> S   32.06  S.pw91-van_ak.UPF
> ATOMIC_POSITIONS {crystal}
> Mo  0.33333333  0.66666667  0.25000000
> Mo  0.66666667  0.33333333  0.75000000
> S   0.33333333  0.66666667  0.62000000
> S   0.66666667  0.33333333  0.12000000
> S   0.66666667  0.33333333 -0.62000000
> S   0.33333333  0.66666667 -0.12000000
> K_POINTS AUTOMATIC
> 12 12 12 1 1 1
>
>
>
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