[Pw_forum] CPO-27-Zn scf not converge

[Tiana Davide]

Ciao Lorenzo

I am not sure but one problem could be that you're using cosab 0.5 (60 degrees) instead of cosab=-0.5 (120 degrees)
another one (again just a guess) is your cut-off seems to be really low even for an ultrasoft pseudopotential.

anyway, you should try with this electron setting

   mixing_mode='local-TF',   
   mixing_beta=0.6,

 I've not problem in converging it (using different pseudo though)

Cheers
Davide

P.S. the last test you can do is to use a bit of smearing, for instance:

   occupations='smearing',
   smearing='marzari-vanderbilt'
   degauss=0.05 
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Message: 2
Date: Sun, 29 May 2016 21:11:49 +0200
From: Lorenzo Don? <lorechimica91 at hotmail.it>
Subject: [Pw_forum] CPO-27-Zn scf not converge
To: PWSCF Forum <pw_forum at pwscf.org>
Message-ID: <BLU436-SMTP367637BD78842FCA03B145CB440 at phx.gbl>
Content-Type: text/plain; charset="us-ascii"

Dear all can you help me or give me some tips to make scf convergence on this calculation:

&control
    pseudo_dir='/home/utente/Scaricati/espresso-5.4.0/pseudo/'
    outdir = './',
    wf_collect = .true.,
    verbosity= high,
/
 &system
    ibrav=  5,
    a= 25.226, cosab= 0.5,  space_group = 148,
    nat=  9, ntyp= 4,
    ecutwfc =15.0,
    occupations='fixed', smearing='gauss',
     input_dft= PBE,
/
 &electrons
    mixing_mode='plain'
    diagonalization='david'
    mixing_beta = 0.01
    conv_thr= 1.0e-4
    electron_maxstep=500,
 /
ATOMIC_SPECIES
Zn 65.409 Zn.pbe-van.UPF
C 12.010  C.pbe-van_ak.UPF
O 16.00   O.pbe-van_ak.UPF
H 1.00    H.pbe-van_ak.UPF
ATOMIC_POSITIONS crystal_sg
  C   7.127430447398E-02 -2.455696438145E-01  7.991093030472E-02
  C   1.197468901477E-01 -2.066445045066E-01  2.152449225957E-01
  C   2.117353032357E-01 -1.117780631842E-01  2.553368090727E-01
  C   1.646071563067E-01 -1.528403540257E-01  1.440875844425E-01
  H   1.629458066146E-01 -1.419696182443E-01 -4.760745519579E-03
 Zn  -1.943259345214E-02  2.834354147594E-01  3.060064447988E-01
  O   7.229455751443E-02 -2.290060932141E-01 -9.085450716092E-02
  O   3.018234203718E-02 -2.947952345384E-01  1.422041978763E-01
  O   2.519030126218E-01 -6.097111538485E-02  1.721974260943E-01
K_POINTS gamma

Thanks a lot to help me

dearly

lorenzo



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