[QE-users] It is neccesary to make a vc-relax in each DFT U+V calculation?

ROBERT MIKHAIL GUZMAN ARELLANO rguzmana at unmsm.edu.pe
Tue Oct 1 08:30:14 CEST 2024


Thanks a lot for your response Iurii.

I have a question about how to use hp.x in parallel. In the article "HP – A
Code for the Calculation of Hubbard Parameters Using Density-Functional
Perturbation Theory," four levels of parallelization are mentioned.

The first can be done using the command "perturb_only_atom(i)." The second
is parallelization over "q" points, the third is parallelization over "k"
points, and the last is plane wave parallelization, which I assume is
automatically enabled, as in pw.x. However, how can I set the "q" and "k"
parallelization for hp.x?

I run hp.x with the assumption that the -nq label is necessary if it
exists. So I use the command:

*mpirun -np 4 hp.x -nq 2 -nk 2 -in name.in <http://name.in> > name.out*
Is it ok?

Please let me know. I was searching on the internet but I did not find an
example of how to run hp.x in parallel using "q" and "k" levels.

Best regards.

El lun, 30 sept 2024 a las 9:38, Timrov Iurii (<iurii.timrov at psi.ch>)
escribió:

> Dear Giuseppe,
>
> The developers of ACBN0 are interested to make it public, but it is not
> clear yet if and when this will happen.
>
> Greetings,
> Iurii
>
> ----------------------------------------------------------
> Dr. Iurii TIMROV
> Tenure-track scientist
> Laboratory for Materials Simulations (LMS)
> Paul Scherrer Institut (PSI)
> CH-5232 Villigen, Switzerland
> +41 56 310 62 14
> https://www.psi.ch/en/lms/people/iurii-timrov
> ------------------------------
> *From:* users <users-bounces at lists.quantum-espresso.org> on behalf of
> Giuseppe Mattioli <giuseppe.mattioli at ism.cnr.it>
> *Sent:* Monday, September 30, 2024 16:18
> *To:* users at lists.quantum-espresso.org <users at lists.quantum-espresso.org>
> *Subject:* Re: [QE-users] It is neccesary to make a vc-relax in each DFT
> U+V calculation?
>
>
> Dear Iurii
> Is there any hope to have the ACBN0 pseudo-hybrid functional or its
> adapted implementation by Lee and Son you mentioned soon available in
> a regular QE version?
> Thanks in advance
> Giuseppe
>
> Quoting Timrov Iurii <iurii.timrov at psi.ch>:
>
> > Dear Robert,
> >
> > Originally, DFT+U and DFT+U+V were introduced to study
> > transition-metal and rare-earth compounds. So usually, U has been
> > applied to d and f electrons, and V for d-p and similar couples.
> >
> > In your system, you have only s and p electrons. Now there are more
> > and more studies where U and V are applied to these electronic
> > states (see e.g.
> >
> https://journals.aps.org/prresearch/abstract/10.1103/PhysRevResearch.2.043410).
> I do not have much experience in using DFT+U and DFT+U+V with U and V from
> linear response for these systems. But I know that ACBN0 is used quite
> extensively for these systems and U and V are
> > positive.
> >
> > HTH
> >
> > Greetings,
> > Iurii
> >
> >
> > ----------------------------------------------------------
> > Dr. Iurii TIMROV
> > Tenure-track scientist
> > Laboratory for Materials Simulations (LMS)
> > Paul Scherrer Institut (PSI)
> > CH-5232 Villigen, Switzerland
> > +41 56 310 62 14
> > https://www.psi.ch/en/lms/people/iurii-timrov
> > ________________________________
> > From: ROBERT MIKHAIL GUZMAN ARELLANO <rguzmana at unmsm.edu.pe>
> > Sent: Saturday, September 28, 2024 02:03
> > To: Timrov Iurii <iurii.timrov at psi.ch>
> > Cc: users at lists.quantum-espresso.org <users at lists.quantum-espresso.org>
> > Subject: Re: [QE-users] It is neccesary to make a vc-relax in each
> > DFT U+V calculation?
> >
> > Thanks a lot for your response.
> >
> > I was reading the paper that you recommended to me and I notice that
> > your U and V values are positive.
> >
> > I am practicing the DFT U + V in graphane (graphene -C- completely
> > hydrogenated - 4 atoms in the unit cell) with the objective to
> > calculate U and V values of carbon and hydrogen orbitals or between
> > them. I used the protocol of your paper and I am considering the HSE
> > band structure calculation as a target, where the last gives a
> > greater gap energy than the GGA DFT calculations.
> >
> > I obtained positive U values but the V values are negatives.
> >
> > These are:
> >
> > ATOMIC_SPECIES
> >  C  12.0107  C.pbe-n-kjpaw_psl.1.0.0.UPF
> >  H   1.008   H.pbe-kjpaw_psl.1.0.0.UPF
> >  ATOMIC_POSITIONS {angstrom}
> > C                0.0000000000        0.0489411798        4.0736189551
> > C                0.0000000000        1.5156118708        3.6147177498
> > H                0.0000000000        0.0493473355        5.1835009290
> > H                0.0000000000        1.5152618823        2.5048489230
> >  K_POINTS {automatic}
> >   12 12 1 0 0 0
> > HUBBARD ortho-atomic
> > V C-2P C-2P 1 1  2.8212
> > V C-2P C-2P 2 2  2.8212
> > V C-2P H-1S 1 3 -0.0283
> > V C-2P H-1S 2 4 -0.0283
> > V C-2P C-2P 1 2 -0.1355
> > V H-1S H-1S 3 3  4.3467
> > V H-1S H-1S 4 4  4.3467
> >
> > So I am wondering what is the criteria to validate or accept a
> > negative V, and another question is which orbitals need to be
> > selected for a V and U calculations.  For example in the commented
> > paper, the Mn-3d and O-2p orbitals are considered but avoided the
> > others valence orbitals.  I am thinking that the most energetic
> > orbitals of each atom must be considered... Could you recommend
> > another work where discuss it ?
> >
> > Thanks for the attention!!
> >
> >
> >
> > El vie, 27 sept 2024 a las 3:01, Timrov Iurii
> > (<iurii.timrov at psi.ch<mailto:iurii.timrov at psi.ch>>) escribió:
> > Dear Robert,
> >
> > Please have a look at this paper:
> > https://journals.aps.org/prb/abstract/10.1103/PhysRevB.103.045141
> >
> > Yes, generally, one should also redo the vc-relax calculations using
> > updated U and V values using DFT+U+V. But if, for example, one wants
> > to work with the fixed geometry (e.g. the experimental one), then
> > obviously there is no need to do the vc-relax calculations.
> >
> > Greetings,
> > Iurii
> >
> > ----------------------------------------------------------
> > Dr. Iurii TIMROV
> > Tenure-track scientist
> > Laboratory for Materials Simulations (LMS)
> > Paul Scherrer Institut (PSI)
> > CH-5232 Villigen, Switzerland
> > +41 56 310 62 14
> > https://www.psi.ch/en/lms/people/iurii-timrov
> > ________________________________
> > From: users
> > <users-bounces at lists.quantum-espresso.org<mailto:
> users-bounces at lists.quantum-espresso.org>> on behalf of ROBERT MIKHAIL
> GUZMAN ARELLANO via users
> > <users at lists.quantum-espresso.org<mailto:
> users at lists.quantum-espresso.org>>
> > Sent: Thursday, September 26, 2024 17:34
> > To:
> > users at lists.quantum-espresso.org<mailto:users at lists.quantum-espresso.org>
>
> > <users at lists.quantum-espresso.org<mailto:
> users at lists.quantum-espresso.org>>
> > Subject: [QE-users] It is neccesary to make a vc-relax in each DFT
> > U+V calculation?
> >
> > Dear members,
> >
> > I am starting to work in DFT U+V making calculations with pw.x and
> > hp.x of Quantum Espresso package. So my question is:
> >
> > In order to calculate the U and V values with hp.x. What is the path
> > to follow?
> >
> > At his time. I am doing these steps.
> >
> > 0. Calibrate pseudo potentials, k-points, and frequency of waves and
> density.
> >
> > 1. Calculate the crystalline structure using vc-relax.
> >
> > 2. Make a scf calculation using the best atomic positions and unit
> > cell parameters obtained in vc-relax calculation. In this
> > calculation, I put a small value of U and V between orbitals. (1.d-3
> > eV)
> >
> > 3 run hp.x in order to calculate better values of U and V.
> >
> > 4 extract the U and V values calculated by hp.x, and put these in a
> > new scf calculation and run the last.
> >
> > 5 repeat the 3 step and after the 4 step until the U and V values
> > between 2 different calculations look equal or with small difference
> > (0.01eV).
> >
> > My Question is: is it necessary to make a vc-relax between the 3 and
> > 4 steps? I looked at some examples which do that  in order to
> > calculate U value,but do not do the same when calculating V
> > (interaction between different orbitals).
> >
> > During this month I have been working with atoms whose valence
> > orbitals are S and P, and I understand that for these orbitals, not
> > being very localized like the D orbitals, it is necessary to work
> > with U and V, where V responds to the coulomb interaction between
> > orbitals of neighboring atoms.
> >
> > Thank's for your attention.
> >
> > Best regards.
>
>
>
> GIUSEPPE MATTIOLI
> CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
> Via Salaria Km 29,300 - C.P. 10
> I-00015 - Monterotondo Scalo (RM)
> Mob (*preferred*) +39 373 7305625
> Tel + 39 06 90672342 - Fax +39 06 90672316
> E-mail: <giuseppe.mattioli at ism.cnr.it>
>
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