[QE-users] using Hybrid functional in QE

[Rameswar Bhattacharjee]

Hi Giuseppe,
Thank you very much for sharing the input sample and your valuable
suggestion. I will try to run a calculation with B3LYP/PBE0 and will see
how it goes.

Rameswar

On Fri, Jan 6, 2023 at 1:58 PM Giuseppe Mattioli <
giuseppe.mattioli at ism.cnr.it> wrote:

>
> Dear Simon
> The lack of pseudopotentials generated using a hybrid functional does
> not represent a significant source of error when using such
> functionals in calculations. I've run tons of B3LYP calculations using
> BLYP pseudopotentals and of PBE0 or HSE calculations using PBE
> pseudopotentials. PBE PPs are easier to find, while BLYP ones may be
> more difficult and sometimes you must (re)generate them yourself.
>
> The input should be something like this (but check all the options in
> the pw input guide as they may be suitable/not suitable for your
> calculations):
>
>   &control
>      calculation = 'relax'
>      restart_mode='from_scratch',
>      prefix='$FILE',
>      pseudo_dir = '$PSEUDO_DIR/',
>      outdir='$TMP_DIR/',
>      nstep=200,
>   /
>   &system
>      ibrav=1, celldm(1)=40.0000,
>      nat=87 ntyp=4,
>      ecutwfc=90.0,
>      ecutfock=130.0,
>      occupations='smearing', degauss=0.01,
>      nspin=1,
>      input_dft='b3lyp'
>      vdw_corr='grimme-d3',
>   /
>   &electrons
>      diagonalization='david',
>      mixing_mode='plain',
>      mixing_beta=0.1,
>      conv_thr=1.0d-6,
>      electron_maxstep=100
>      adaptive_thr=.true.
>   /
>   &ions
>      ion_dynamics='bfgs'
>   /
> ATOMIC_SPECIES
> O    15.999     O.blyp-mt.UPF
> N    14.007     N.blyp-mt.UPF
> C    12.011     C.blyp-mt.UPF
> H     1.008     H.blyp-vbc.UPF
> ATOMIC_POSITIONS {angstrom}
> ...
> K_POINTS {gamma}
>
> NB: I always recommend the use of norm-conserving pseudopotentials (in
> this case they are rather old but very well tested pseudopotentials
> that used to be in the QE repo, but you can generate BLYP PPs using
> the "atomic" ld1.x code and the PSlibrary, or even the ONCV generation
> code) when performing EXX calculations.
> HTH
> Giuseppe
>
> Quoting Rameswar Bhattacharjee <rb1820 at georgetown.edu>:
>
> > Hi Simon,
> > Thank you for the information. I have gone through the input_dft and it
> > looks like I can use PBE0 or B3LYP. But I am not sure for that case which
> > pseudopotential I should use. Could you (or anyone) have a sample input
> to
> > run a QUE calculation using the B3LYP functional? That would be very
> > helpful. Thank you
> >
> > Rameswar
> >
> > On Fri, Jan 6, 2023 at 11:34 AM Simon Imanuel Rombauer <
> > simon.rombauer at student.uni-augsburg.de> wrote:
> >
> >> Hello Rameswar,
> >>
> >> see 'input_dft' option in the documentation, see Modules/funct.f90 for
> >> possible functionals.
> >> Best,
> >> Simon
> >>
> >> Am Freitag, Januar 06, 2023 17:00 CET, schrieb Rameswar Bhattacharjee <
> >> rb1820 at georgetown.edu>:
> >>
> >> > Hi Everyone,
> >> > I wonder if I can use hybrid functionals such as PBE0 or B3LYP in QE
> for
> >> > ground state calculation. All the pseudopotentials I found on the
> website
> >> > are for PBE. But I need an exchange-correlation functional (not pure)
> to
> >> > calculate the band gap more accurately.
> >> >
> >> > Any suggestions would be appreciated. Thank you.
> >> >
> >> > Rameswar Bhattacharjee
> >> > PostDoc
> >> > Georgetown University
> >>
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>
>
> GIUSEPPE MATTIOLI
> CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
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>
> _______________________________________________
> The Quantum ESPRESSO community stands by the Ukrainian
> people and expresses its concerns about the devastating
> effects that the Russian military offensive has on their
> country and on the free and peaceful scientific, cultural,
> and economic cooperation amongst peoples
> _______________________________________________
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
> users mailing list users at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users
>
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