[Pw_forum] Cell geometry optimization issue

[Paolo Giannozzi]

Add a small smearing, increase the threshold to 1.0d-8 or even 1.0d-6

Paolo

On Fri, Nov 6, 2015 at 2:59 PM, Arijan Aleksić <aaleksic at fizika.unios.hr>
wrote:

> Dear all,
>
> I am working on geometry optimization for WTe2 (Tungsten(IV) telluride).
> When running calculations, they failed to converge within limits in 100
> iterations.
>
> First I have increased cell parameters for 10-15% to check if there will
> be any difference (also had big pressure). Next I went with reducing
> mixing_beta in steps of 0.1 to check for any changes which yielded no good
> results. And finally I used calculation = 'vc-relax' which gave even worse
> results and could not optimize the cell.
>
> I will accept any advice on what should be my next action in order to
> succeed in getting optimization complete.
>
> Here is the text from input file I used (version of Quantum Espresso is
> 5.2.1):
>
>  &control
>     calculation  = 'vc-relax',
>     restart_mode = 'from_scratch',
>     prefix       = 'wte2',
>     tprnfor      = .true.,
>     pseudo_dir   = '/home/aaleksic/Pseudo/',
>     outdir       = '/home/aaleksic/wte2/tmp/',
>  /
>
>  &system
>     ibrav     = 8,
>     celldm(1) = 13,
>     celldm(2) = 0.53846,
>     celldm(3) = 2.15385,
>     nat       = 24,
>     ntyp      = 2,
>     nbnd      = 74,
>     ecutwfc   = 100.0,
>  /
>
>  &electrons
>     mixing_beta = 0.1,
>     conv_thr    = 1.0d-12,
>  /
>
>  &ions
>  /
>
>  &cell
>  /
>
> ATOMIC_SPECIES
>  W   74.0   W.pbe-mt_fhi.UPF
>  Te  52.0   Te.pbe-mt_fhi.UPF
>
> ATOMIC_POSITIONS (crystal)
> W   0.90050000000  0.5000000000  0.00000000000
> Te  0.29410000000  0.5000000000  0.09650000000
> Te  0.80020000000  0.0000000000  0.14000000000
> W   0.54140000000  0.0000000000  0.98510000000
> Te  0.35590000000  0.0000000000  0.34490000000
> Te  0.85170000000  0.5000000000  0.38930000000
> W   0.59950000000  0.5000000000  0.50000000000
> Te  0.20590000000  0.5000000000  0.59650000000
> Te  0.69980000000  0.0000000000  0.64000000000
> W   0.95860000000  0.0000000000  0.48510000000
> Te  0.14410000000  0.0000000000  0.84490000000
> Te  0.64830000000  0.5000000000  0.88930000000
> W   0.40050000000  0.5000000000  0.50000000000
> Te  0.79410000000  0.5000000000  0.59650000000
> Te  0.30020000000  0.0000000000  0.64000000000
> W   0.04140000000  0.0000000000  0.48510000000
> Te  0.85590000000  0.0000000000  0.84490000000
> Te  0.35170000000  0.5000000000  0.88930000000
> W   0.09950000000  0.5000000000  0.00000000000
> Te  0.70590000000  0.5000000000  0.09650000000
> Te  0.19980000000  0.0000000000  0.14000000000
> W   0.45860000000  0.0000000000  0.98510000000
> Te  0.64410000000  0.0000000000  0.34490000000
> Te  0.14830000000  0.5000000000  0.38930000000
>
>
>
> K_POINTS (automatic)
> 4 4 4 0 0 0
>
> Thank you.
>
> Best regards,
> Arijan Aleksic,
> University J.J.Strossmayer, Croatia.
>
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>



-- 
Paolo Giannozzi, Dept. Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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