[Pw_forum] Instability of Ni pseudopotential from PW_Library

[Nicola Marzari]

Dear Merlin,


actually for Ni high-accuracy I would go for GBRV 1.4 - it
is much closer to the all-electron equation of state.
See the pseudopotential tests on the Materials Cloud:

http://materialscloud.org/sssp

If you want to solve the phonon issue, maybe tighten even more
the tolerance on the total energy scf calculation, and then
decrease the default mixing parameters (eg alpha_mix) in the
phonon code:
http://www.quantum-espresso.org/wp-content/uploads/Doc/INPUT_PH.html


				nicola





On 14/08/2016 12:41, Merlin Meheut wrote:
> Dear pwscf users and developpers,
>
> I am trying to use the "high accuracy" Ni pseudopotential from pwlibrary
> v1.0.0 Ni.pbe-spn-rrkjus_psl.1.0.0.UPF and I have trouble making it
> converge for phonon calculations. For example, for fcc nickel metal out
> of the Brillouin zone (q=-0.25, 0.25, -0.25), see inputs below. Would
> you have any suggestions on fixing this problem?
>
> scf input:
> --------------------
> Ni metal
>  &control
>        calculation = 'scf',
>       restart_mode = 'from_scratch' ,
>             prefix = 'NIMH',
>            disk_io = 'default' ,
>     pseudo_dir     = './',
>     outdir         ='/tmpdir/$LOGNAME/',
>     tprnfor        = .true.,
>     tstress        = .true.,
> /&end
>
> &system
>    ibrav=2, celldm(1)=6.659,
>  nat=1, ntyp=1, ecutwfc=110.0, ecutrho=660.0,
>    nspin=2, starting_magnetization(1)=0.5, occupations='smearing',
> smearing='mp', degauss=0.02,
> /&end
>
>  &electrons
>    electron_maxstep = 80,
>           conv_thr = 1.d-7,
>        mixing_mode = 'plain',
>        startingwfc = 'atomic',
>        mixing_beta = 0.5,
> /&end
>
> ATOMIC_SPECIES
>   Ni  57.9353   Ni.pbe-spn-rrkjus_psl.1.0.0.UPF
>
> ATOMIC_POSITIONS crystal
> Ni     0.000000000         0.000000000         0.000000000
>
> K_POINTS  (automatic)
> 10 10 10 1 1 1
> ---------------------
>
> ph input:
> ---------------------
> Ni metal
>  &inputph
>   tr2_ph=1.0d-17,
>   prefix='NIMH',
>   amass(1)=57.9353,
>   outdir='/tmpdir/$LOGNAME/',
>   fildyn='mat.${PREFIX}',
>  /&end
>  -0.2500000   0.2500000  -0.2500000
> -----------------------
>
> Thank you very much for any help,
>
> Best regards,
>
> Merlin Méheut
>
>
>
> --
> Merlin Méheut
> adresse labo:
> GET - OMP   - Université Paul Sabatier
> 14 avenue Edouard Belin
> 31400 Toulouse
> FRANCE
> tel: (+33) 5 61 33 26 17
>
>
>
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-- 
----------------------------------------------------------------------
Prof Nicola Marzari, Chair of Theory and Simulation of Materials, EPFL
Director, National Centre for Competence in Research NCCR MARVEL, EPFL
http://theossrv1.epfl.ch/Main/Contact http://nccr-marvel.ch/en/project