[QE-users] DOS Calculation for a Molecule of Water

Dan Gil dan.gil9973 at gmail.com
Thu Dec 6 21:46:02 CET 2018


Hi,

I am trying out a DOS calculation for a molecule of water, however, my
results are very inaccurate compared to literature (
http://www1.lsbu.ac.uk/water/water_methods.html). I was wondering if you
could give me some advice on improving my results. I am expecting states at
-14, -15, -19, and -37 eV. Instead, I am getting states at -7, -9, -13, and
-25 eV.

I am first carrying out an SCF calculation of a water molecule (pw.x) and
then obtaining the density of states (dos.x). The structure of water is
already relaxed.

The relevant files are contained below.

- - - - - -water.pw.in
&control
    calculation='scf',
    wf_collect = .true. ,
    outdir = 'water' ,
    restart_mode = 'from_scratch' ,
    pseudo_dir = 'pseudo' ,
    disk_io = 'low' ,
    verbosity = 'low' ,
    max_seconds = 68000 ,
 /
 &system
    ibrav = 4,
    celldm(1)=19.174,
    celldm(3)=1,
    nat = 3 ,
    ntyp = 2 ,
    ecutwfc = 70.0,
    ecutrho = 560.0,
    smearing='gaussian',
    occupations='fixed',
 /
 &electrons
    diagonalization='david',
    mixing_mode = 'local-TF',
 /
 &ions
 /
ATOMIC_SPECIES
O    15.999   O.pbe-n-rrkjus_psl.1.0.0.UPF
H    1.00794  H.pbe-rrkjus_psl.1.0.0.UPF
ATOMIC_POSITIONS crystal
H        0.003478196   0.090739324   0.224999603
H        0.090739324   0.003478196   0.224999603
O        0.105782480   0.105782480   0.225000794
K_POINTS gamma
- - - - - -

- - - - - - get.dos.in
 &dos
                      outdir = 'water' ,
                     DeltaE  = .1
 /
- - - - - -

- - - - - - pwscf.dos
#  E (eV)   dos(E)     Int dos(E) EFermi =   0.000 eV
 -25.473  0.1393E-02  0.1393E-03
 -25.373  0.2067E+00  0.2081E-01
 -25.273  0.4151E+01  0.4359E+00
 -25.173  0.1128E+02  0.1564E+01
 -25.073  0.4151E+01  0.1979E+01
 -24.973  0.2067E+00  0.2000E+01
 -24.873  0.1393E-02  0.2000E+01
 -24.773  0.1270E-05  0.2000E+01
 -24.673  0.1567E-09  0.2000E+01
 -24.573  0.2617E-14  0.2000E+01
 -24.473  0.5916E-20  0.2000E+01
 -24.373  0.1810E-26  0.2000E+01
 -24.273  0.7492E-34  0.2000E+01
 -24.173  0.4198E-42  0.2000E+01
 -24.073  0.3183E-51  0.2000E+01
 -23.973  0.3266E-61  0.2000E+01
 -23.873  0.4536E-72  0.2000E+01
 -23.773  0.8994E-84  0.2000E+01
 -23.673  0.6246E-85  0.2000E+01
 -23.573  0.6246E-85  0.2000E+01
 -23.473  0.6246E-85  0.2000E+01
 -23.373  0.6246E-85  0.2000E+01
 -23.273  0.6246E-85  0.2000E+01
 -23.173  0.6246E-85  0.2000E+01
 -23.073  0.6246E-85  0.2000E+01
 -22.973  0.6246E-85  0.2000E+01
 -22.873  0.6246E-85  0.2000E+01
 -22.773  0.6246E-85  0.2000E+01
 -22.673  0.6246E-85  0.2000E+01
 -22.573  0.6246E-85  0.2000E+01
 -22.473  0.6246E-85  0.2000E+01
 -22.373  0.6246E-85  0.2000E+01
 -22.273  0.6246E-85  0.2000E+01
 -22.173  0.6246E-85  0.2000E+01
 -22.073  0.6246E-85  0.2000E+01
 -21.973  0.6246E-85  0.2000E+01
 -21.873  0.6246E-85  0.2000E+01
 -21.773  0.6246E-85  0.2000E+01
 -21.673  0.6246E-85  0.2000E+01
 -21.573  0.6246E-85  0.2000E+01
 -21.473  0.6246E-85  0.2000E+01
 -21.373  0.6246E-85  0.2000E+01
 -21.273  0.6246E-85  0.2000E+01
 -21.173  0.6246E-85  0.2000E+01
 -21.073  0.6246E-85  0.2000E+01
 -20.973  0.6246E-85  0.2000E+01
 -20.873  0.6246E-85  0.2000E+01
 -20.773  0.6246E-85  0.2000E+01
 -20.673  0.6246E-85  0.2000E+01
 -20.573  0.6246E-85  0.2000E+01
 -20.473  0.6246E-85  0.2000E+01
 -20.373  0.6246E-85  0.2000E+01
 -20.273  0.6246E-85  0.2000E+01
 -20.173  0.6246E-85  0.2000E+01
 -20.073  0.6246E-85  0.2000E+01
 -19.973  0.6246E-85  0.2000E+01
 -19.873  0.6246E-85  0.2000E+01
 -19.773  0.6246E-85  0.2000E+01
 -19.673  0.6246E-85  0.2000E+01
 -19.573  0.6246E-85  0.2000E+01
 -19.473  0.6246E-85  0.2000E+01
 -19.373  0.6246E-85  0.2000E+01
 -19.273  0.6246E-85  0.2000E+01
 -19.173  0.6246E-85  0.2000E+01
 -19.073  0.6246E-85  0.2000E+01
 -18.973  0.6246E-85  0.2000E+01
 -18.873  0.6246E-85  0.2000E+01
 -18.773  0.6246E-85  0.2000E+01
 -18.673  0.6246E-85  0.2000E+01
 -18.573  0.6246E-85  0.2000E+01
 -18.473  0.6246E-85  0.2000E+01
 -18.373  0.6246E-85  0.2000E+01
 -18.273  0.6246E-85  0.2000E+01
 -18.173  0.6246E-85  0.2000E+01
 -18.073  0.6246E-85  0.2000E+01
 -17.973  0.6246E-85  0.2000E+01
 -17.873  0.6246E-85  0.2000E+01
 -17.773  0.6246E-85  0.2000E+01
 -17.673  0.6246E-85  0.2000E+01
 -17.573  0.6246E-85  0.2000E+01
 -17.473  0.6246E-85  0.2000E+01
 -17.373  0.6246E-85  0.2000E+01
 -17.273  0.6246E-85  0.2000E+01
 -17.173  0.6246E-85  0.2000E+01
 -17.073  0.6246E-85  0.2000E+01
 -16.973  0.6246E-85  0.2000E+01
 -16.873  0.6246E-85  0.2000E+01
 -16.773  0.6246E-85  0.2000E+01
 -16.673  0.6246E-85  0.2000E+01
 -16.573  0.6246E-85  0.2000E+01
 -16.473  0.6246E-85  0.2000E+01
 -16.373  0.6246E-85  0.2000E+01
 -16.273  0.6246E-85  0.2000E+01
 -16.173  0.6246E-85  0.2000E+01
 -16.073  0.6246E-85  0.2000E+01
 -15.973  0.6246E-85  0.2000E+01
 -15.873  0.6246E-85  0.2000E+01
 -15.773  0.6246E-85  0.2000E+01
 -15.673  0.6246E-85  0.2000E+01
 -15.573  0.6246E-85  0.2000E+01
 -15.473  0.6246E-85  0.2000E+01
 -15.373  0.6246E-85  0.2000E+01
 -15.273  0.6246E-85  0.2000E+01
 -15.173  0.6246E-85  0.2000E+01
 -15.073  0.6246E-85  0.2000E+01
 -14.973  0.6246E-85  0.2000E+01
 -14.873  0.6246E-85  0.2000E+01
 -14.773  0.6246E-85  0.2000E+01
 -14.673  0.6246E-85  0.2000E+01
 -14.573  0.6246E-85  0.2000E+01
 -14.473  0.6246E-85  0.2000E+01
 -14.373  0.6326E-85  0.2000E+01
 -14.273  0.1156E-73  0.2000E+01
 -14.173  0.1102E-62  0.2000E+01
 -14.073  0.1422E-52  0.2000E+01
 -13.973  0.2484E-43  0.2000E+01
 -13.873  0.5870E-35  0.2000E+01
 -13.773  0.1878E-27  0.2000E+01
 -13.673  0.8127E-21  0.2000E+01
 -13.573  0.4761E-15  0.2000E+01
 -13.473  0.3775E-10  0.2000E+01
 -13.373  0.4050E-06  0.2000E+01
 -13.273  0.5881E-03  0.2000E+01
 -13.173  0.1156E+00  0.2012E+01
 -13.073  0.3074E+01  0.2319E+01
 -12.973  0.1106E+02  0.3426E+01
 -12.873  0.5389E+01  0.3964E+01
 -12.773  0.3553E+00  0.4000E+01
 -12.673  0.3170E-02  0.4000E+01
 -12.573  0.3827E-05  0.4000E+01
 -12.473  0.6255E-09  0.4000E+01
 -12.373  0.1383E-13  0.4000E+01
 -12.273  0.4140E-19  0.4000E+01
 -12.173  0.1677E-25  0.4000E+01
 -12.073  0.9192E-33  0.4000E+01
 -11.973  0.6820E-41  0.4000E+01
 -11.873  0.6847E-50  0.4000E+01
 -11.773  0.9304E-60  0.4000E+01
 -11.673  0.1711E-70  0.4000E+01
 -11.573  0.4263E-82  0.4000E+01
 -11.473  0.6246E-85  0.4000E+01
 -11.373  0.6246E-85  0.4000E+01
 -11.273  0.6246E-85  0.4000E+01
 -11.173  0.6246E-85  0.4000E+01
 -11.073  0.6246E-85  0.4000E+01
 -10.973  0.6246E-85  0.4000E+01
 -10.873  0.6246E-85  0.4000E+01
 -10.773  0.6246E-85  0.4000E+01
 -10.673  0.6246E-85  0.4000E+01
 -10.573  0.8307E-84  0.4000E+01
 -10.473  0.4196E-72  0.4000E+01
 -10.373  0.3039E-61  0.4000E+01
 -10.273  0.2979E-51  0.4000E+01
 -10.173  0.3953E-42  0.4000E+01
 -10.073  0.7098E-34  0.4000E+01
  -9.973  0.1725E-26  0.4000E+01
  -9.873  0.5672E-20  0.4000E+01
  -9.773  0.2525E-14  0.4000E+01
  -9.673  0.1521E-09  0.4000E+01
  -9.573  0.1240E-05  0.4000E+01
  -9.473  0.1368E-02  0.4000E+01
  -9.373  0.2042E+00  0.4021E+01
  -9.273  0.4126E+01  0.4434E+01
  -9.173  0.1128E+02  0.5562E+01
  -9.073  0.4176E+01  0.5979E+01
  -8.973  0.2092E+00  0.6000E+01
  -8.873  0.1418E-02  0.6001E+01
  -8.773  0.1301E-05  0.6001E+01
  -8.673  0.1615E-09  0.6001E+01
  -8.573  0.2713E-14  0.6001E+01
  -8.473  0.6170E-20  0.6001E+01
  -8.373  0.1899E-26  0.6001E+01
  -8.273  0.7908E-34  0.6001E+01
  -8.173  0.4457E-42  0.6001E+01
  -8.073  0.1524E-39  0.6001E+01
  -7.973  0.1495E-31  0.6001E+01
  -7.873  0.1985E-24  0.6001E+01
  -7.773  0.3567E-18  0.6001E+01
  -7.673  0.8674E-13  0.6001E+01
  -7.573  0.2855E-08  0.6001E+01
  -7.473  0.1272E-04  0.6001E+01
  -7.373  0.7666E-02  0.6001E+01
  -7.273  0.6254E+00  0.6064E+01
  -7.173  0.6905E+01  0.6754E+01
  -7.073  0.1032E+02  0.7786E+01
  -6.973  0.2086E+01  0.7995E+01
  -6.873  0.5710E-01  0.8000E+01
- - - - - -

Best Regards,

Dan Gil
PhD Candidate
Department of Chemical and Biomolecular Engineering
Case Western Reserve University
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