Re: [QE-users] Problem of HSE scf calculation with QE code

ygxu17 Fri, 10 Jul 2020 06:38:41 -0700

Hello Lorenzo,

Thanks for you advice. I tried nqx1=nqx2=nqx3=2 and got the value of 1.33 eV for the gamma point gap. It seems the problem comes from the sampling mesh grid.

However, as is known, HSE calculation is expensive. In my calculation of TiO2, 240 atoms and gamma_only kpoints are used. How should I set the nqx for this calculation from your experience?('1 1 1' fails to reproduce the bandgap.) By the way, is there any advice to speed up the HSE scf calculation?

&CONTROL

title = 'TiO2'

calculation = 'scf'

restart_mode = 'from_scratch'

outdir = './1/'

pseudo_dir = './'

prefix = 'C'

tstress = .true.

tprnfor = .true.

wf_collect=.true.

disk_io = 'low'

verbosity = 'high'

&SYSTEM

ibrav = 0

nat = 240

ntyp = 2

ecutwfc = 90

ecutfock = 180

nosym = .true.

tot_charge = 0

!nbnd=20

occupations='smearing', smearing='gaussian', degauss=0.002

input_dft = 'hse'

nqx1 = 1

nqx2 = 1

nqx3 = 1

exx_fraction = 0.25

&ELECTRONS

diagonalization = 'david'

conv_thr = 1.0D-6

adaptive_thr = .true.

mixing_beta = 0.7

electron_maxstep=100

&IONS

ion_dynamics = 'bfgs'

ATOMIC_SPECIES

Ti 47.867 Ti.SG15.PBE.UPF

O 15.999 O.SG15.PBE.UPF

K_POINTS gamma

CELL_PARAMETERS bohr

22.2322500562796 0.000000000000000E+000 0.000000000000000E+000

0.000000000000000E+000 24.3827575075721 0.000000000000000E+000

0.000000000000000E+000 0.000000000000000E+000 57.4954854151373

ATOMIC_POSITIONS bohr

Ti 0.000000000000000E+000 6.09568937689302 2.41706800158272

Ti 0.000000000000000E+000 0.000000000000000E+000 7.80624023418306

Ti 0.000000000000000E+000 6.09568937689302 14.8977770162714

Ti 0.000000000000000E+000 0.000000000000000E+000 20.6787177547025

Ti 0.000000000000000E+000 6.09568937689302 27.2633365743639

Ti 2.77903125703495 0.000000000000000E+000 1.45370321265824

...

Best regards,

Greg Xu

On 7/10/2020 16:17，Lorenzo Paulatto<[email protected]> wrote：

nqx1 = 1
nqx2 = 1
nqx3 = 1
Hello Greg,
these choce of parameters is cheap, but not very well converged. Did you
try to use a finer grid for exchange?

cheers

--
Lorenzo Paulatto - Paris
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_______________________________________________
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users mailing list [email protected]
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Re: [QE-users] Problem of HSE scf calculation with QE code

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