[Pw_forum] Hybrid Calculation

[Manu Hegde]

I am not that expert in hybrid density functional theory. But looking into
your input seems like you have large cut-off. First start with some simple
assumptions. Just follow the example in QE libraray. Make sure it works.
Also you need lot of memory. Hope it helps.
Manu
(University of Waterloo)

On Dec 28, 2017 1:39 PM, "Chemist" <mrbsmith58 at gmail.com> wrote:

Hello,

I am attempting to run a hybrid scf calculation on a Pb doped V-oxide
structure, and I have two questions.

1) In general, does my input file for such a calculation look correct?
(input = below)

2) When running this calculation, I notice that my code crashes with the
error "dexx is negative!". After doing some searching through the archives,
The advice suggests to try different exxdiv_treatments - but this gives me
a host of new problems, such as knowing which ecutvcut to use (and why),
etc.

I am hoping that someone with expertise can help steer me in the correct
direction. My input is below. The value for ecut was found by doing a
convergence study at the gamma point.

Thank you for your time,
Best,

Brendan Smith
State University of New York at Buffalo, Ph.D Student, 2nd Year


&CONTROL
  calculation = 'scf',
  nstep = 50,
  pseudo_dir = '/projects/academic/alexeyak/brendan/PSEDUO/norm_
conserving/non_rel/',
  outdir = './',
  prefix = 'x',
  disk_io = 'low',
/

&SYSTEM
  ibrav = 0,
  nat = 46,
  ntyp = 3,
  nspin = 1,
  nbnd = 235,
  ecutwfc = 90,
  ecutrho = 720,
  occupations = 'smearing',
  smearing = 'gaussian',
  degauss = 0.005,
  nosym = .true.,
  input_dft = 'PBE0'
/

&ELECTRONS
  electron_maxstep = 300,
  conv_thr = 1.D-7,
  mixing_beta = 0.35,
/

ATOMIC_SPECIES
 Pb  207.2     Pb.pbe-mt_fhi.UPF
 V   50.9415   V.pbe-mt_fhi.UPF
 O   15.9994   O.pbe-mt_fhi.UPF

K_POINTS automatic
 1 1 1 0 0 0

CELL_PARAMETERS angstrom
       15.4779996872         0.0000000000         0.0000000000
        0.0000000000         3.6440000534         0.0000000000
       -3.3441298425         0.0000000000         9.5546809225

ATOMIC_POSITIONS angstrom
Pb    -1.252373291         0.000000000         3.769703925
Pb    13.386243452         0.000000000         5.784976998
Pb     6.486626236         1.822000027         3.769703925
Pb     5.647243147         1.822000027         5.784976998
V     4.861534709         0.000000000         0.938269674
V     7.272335672         0.000000000         8.616411034
V    12.600534091         1.822000027         0.938269674
V    -0.466664633         1.822000027         8.616411034
V     1.427260535         0.000000000         1.105476574
V    10.706608873         0.000000000         8.449204278
V     9.166260840         1.822000027         1.105476574
V     2.967609491         1.822000027         8.449204278
V     3.038442017         0.000000000         3.899265370
V     9.095428288         0.000000000         5.655415552
V    10.777441400         1.822000027         3.899265370
V     1.356427984         1.822000027         5.655415552
O     0.000000000         0.000000000         0.000000000
O     7.738999844         1.822000027         0.000000000
O    12.419713211         0.000000000         0.481555919
O    -0.285843304         0.000000000         9.073124825
O     4.680713367         1.822000027         0.481555919
O     7.453156540         1.822000027         9.073124825
O     9.548904122         0.000000000         0.741443261
O     2.584965723         0.000000000         8.813237661
O     1.809904278         1.822000027         0.741443261
O    10.323965566         1.822000027         8.813237661
O     6.011811013         0.000000000         2.064766617
O     6.122059193         0.000000000         7.489914590
O    13.750810395         1.822000027         2.064766617
O    -1.616941112         1.822000027         7.489914590
O     3.327103622         0.000000000         2.120183708
O     8.806766173         0.000000000         7.434497357
O    11.066103466         1.822000027         2.120183708
O     1.067766329         1.822000027         7.434497357
O     0.784110151         0.000000000         2.606516942
O    11.349759479         0.000000000         6.948164266
O     8.523110110         1.822000027         2.606516942
O     3.610759635         1.822000027         6.948164266
O    10.287975715         0.000000000         4.055961942
O     1.845894129         0.000000000         5.498718980
O     2.548975872         1.822000027         4.055961942
O     9.584893973         1.822000027         5.498718980
O     4.533116432         0.000000000         4.489744680
O     7.600753412         0.000000000         5.064936242
O    12.272116276         1.822000027         4.489744680
O    -0.138246431         1.822000027         5.064936242


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