[Pw_forum] Frequency Dependent Dielectric Function (Layla Martin-Samos)

[Paolo Giannozzi]

On Mon, 2012-12-03 at 09:34 +0100, Layla Martin-Samos wrote:

> Hi, you could try to use a larger smearing (larger degauss).

and a more appropriate one: 'fermi-dirac' is known to yield
very slow convergence wrt the k-point grid. Try 'marzari-vanderbilt'
or 'methfessel-paxton'

P.
> 
> 
> cheers
> 
> 
> Layla
> 
> 2012/11/30 Tsogbadrakh N <Tsogbadrakh at num.edu.mn>
>         Hello All,
>         
>         I am calculating the optimization of MoS2 with the non
>         collinear calculation with spin orbit interaction using the
>         full relativistic ultra soft pseudo potential.  The non
>         magnetic calculation with spin orbit interaction is ok.
>         
>         Here the SCF iteration does not converge.
>         
>         Please advice me
>          
>         The input file is written  on below.
>         
>         &control
>             calculation = 'relax',
>             restart_mode='from_scratch',
>             title = 'Bulk_MoS2_SP2_SOI_exp_unit_cell',
>             prefix='Bulk_MoS2_SP2_SOI_exp',
>             verbosity = 'high',
>             pseudo_dir =  './',
>             outdir='./',
>             etot_conv_thr = 1.0E-4,
>             forc_conv_thr = 1.0D-3,
>             tstress = .true.,
>             tprnfor = .true.,
>            /
>         &system
>             ibrav=4,
>             celldm(1) = 5.97153412390939732180,
>             celldm(3) = 3.89050632911392405063,
>             nat=6, ntyp=2,
>             nspin=1,
>             starting_magnetization(1) = -1.0,
>             starting_magnetization(2) =  1.0,
>             ecutwfc=30.0, ecutrho=500.0,
>             occupations='smearing', smearing='fermi-dirac',
>         degauss=0.001,
>             input_dft  =  'PBE',
>             noncolin = .true.,
>             lspinorb = .true.,
>            /
>         &electrons
>             electron_maxstep  =  2000,
>             conv_thr  =  1.0d-8,
>             mixing_mode  =  'plain',
>             mixing_beta = 0.05,
>             mixing_ndim = 10,
>             diagonalization   =  'cg',
>          /
>         &IONS
>             ion_dynamics = 'bfgs',
>             upscale   = 100D0,
>             trust_radius_max = 0.8D0,
>             trust_radius_min = 1.D-3,
>             trust_radius_ini = 0.5D0,
>          /
>         ATOMIC_SPECIES
>           S    32.065   S.rel-pbe-n-rrkjus_psl.0.1.UPF
>           Mo   95.960   Mo.rel-pbe-spn-rrkjus_psl.0.2.UPF
>         ATOMIC_POSITIONS {crystal}
>                   S     0.3333333  0.6666667  0.6323308
>                   S    -0.3333333 -0.6666667  0.1323308
>                   S     0.6666667  0.3333333 -0.6323308
>                   S    -0.6666667 -0.3333333 -0.1323308
>                   Mo    0.3333333  0.6666667  0.2500000
>                   Mo   -0.3333333 -0.6666667  0.7500000
>         K_POINTS automatic
>         8  8  4  0  0  0
>         -------
>         
>         Dr. Tsogbadrakh Namsrai 
>         
>         
>         
>         
>         
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> 
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-- 
Paolo Giannozzi, IOM-Democritos and University of Udine, Italy