[Pw_forum] HSE Screening Parameter

[Ref Fymz]

Dear pw_forum,


I am trying to use the HSE hybrid functional within quantum espresso, I
have an 8 atom cubic silicon cell, and I have converged my k-point grid,
q-point grid, and my wavefunction ecut. However, regardless of how much I
change my screening parameter (from 0.0 bohr^-1 all the way to 100
bohr^-1), the difference between my lowest unoccupied and highest occupied
state remains about 0.61 eV, this points towards a problem. Can anybody
point me in the right direction?

Also, when I do an scf run, I'm not getting the pressures / forces printed
in the file, despite asking for them, is this due to the density of my
k-point and q-point grid?

The only other thing I can think it could be from is the ecutvcut /
x_gamma_extrapolation / exxdiv_treatment. Has anybody else used QE for
silicon successfully?

My input looks like this;

 &control
    prefix='silicon',
    pseudo_dir = 'espresso/pseudo/',
    outdir='./tmp'
    tprnfor = .true.
    tstress = .true.
    restart_mode = 'from_scratch'

 /
 &system
    ibrav = 1, celldm(1) =10.327, nat= 8, ntyp= 1,
    ecutwfc = 120, input_dft = 'hse'
    nqx1 = 8, nqx2 = 8, nqx3 = 8
    nbnd = 32
    screening_parameter = 100
    occupations = 'fixed'
 /
 &electrons
    diagonalization='cg'
    conv_thr = 1.0e-9
 /
ATOMIC_SPECIES
 Si 28.086 Si.pbe-mt_fhi.UPF

ATOMIC_POSITIONS alat
 Si 0.0   0.0  0.0
 Si 0.5   0.5  0.0
 Si 0.5   0.0  0.5
 Si 0.0   0.5  0.5
 Si 0.25 0.25 0.25
 Si 0.75 0.75 0.25
 Si 0.75 0.25 0.75
 Si 0.25 0.75 0.75

K_POINTS automatic
24 24 24 0 0 0



I would also like to add that when I add a F-D smearing temperature, my
output still only gives me the total energy (it seems to abort before
printing the breakdown of TS / XC / hartree / one electron / etc). Is this
also because of my dense kpoint grid? My output has this line a the end.

"
 Primary job  terminated normally, but 1 process returned
a non-zero exit code.. Per user-direction, the job has been aborted.
-------------------------------------------------------
--------------------------------------------------------------------------
mpirun detected that one or more processes exited with non-zero status,
thus causing
the job to be terminated. The first process to do so was:

  Process name: [[44615,1],12]
  Exit code:    127
"

Thanks again, hope you can shed some light on this for me,



Thanks,


Phil
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