[Pw_forum] R: Re: HSE vs PBE
Giuseppe Mattioli
giuseppe.mattioli at ism.cnr.it
Thu May 24 17:41:28 CEST 2012
> Do you mean that hybrid calcs can be performed only with Norm Conserving
> ones?
Yes, absolutely...:-(
On Thursday 24 May 2012 16:16:27 giacsport at libero.it wrote:
> Dear Giuseppe,
> really thanks for the very clear and helpful
> reply.
>
> But let me ask you this.
>
> From the psesudo library of PWSCF I took the
>
> Cu.pbe-n-van.UPF (hard to say...I dont find it anymore in the
> database....has the database been changed recently?...anyway the header of
> the pseudo is reported below)
>
> pseudo that is a USPP one.
>
> Do you mean that hybrid calcs can be performed only with Norm Conserving
> ones?
>
> :'(
>
> Thanks once more!
>
> Best,
> Giacomo
>
>
> the pseudo header
>
> <PP_INFO>
> Generated using Vanderbilt code, version 7 3
> 4
> Author: unknown Generation date: 4 3
> 5
> Automatically converted from original
> format
> 1 The Pseudo was generated with a Scalar-Relativistic
> Calculation 2.00000000000E+00 Local Potential cutoff radius
> nl pn l occ Rcut Rcut US E pseu
> 3D 3 2 9.50 10.00000000000 2.00000000000 -0.60492460120
> 4S 4 0 1.00 10.00000000000 2.10000000000 -0.43710222811
> 4P 4 1 0.50 10.00000000000 2.20000000000 -0.10740671642
> </PP_INFO>
>
>
> <PP_HEADER>
> 0 Version Number
> Cu Element
> US Ultrasoft pseudopotential
> T Nonlinear Core Correction
> SLA PW PBE PBE PBE Exchange-Correlation functional
> 11.00000000000 Z valence
> -121.01063523375 Total energy
> 0.0000000 0.0000000 Suggested cutoff for wfc and rho
> 2 Max angular momentum component
> 867 Number of points in mesh
> 3 6 Number of Wavefunctions, Number of Projectors
> Wavefunctions nl l occ
> 3D 2 9.50
> 4S 0 1.00
> 4P 1 0.50
> </PP_HEADER>
>
> >----Messaggio originale----
> >Da: giuseppe.mattioli at ism.cnr.it
> >Data: 24/05/2012 11.27
> >A: "giacsport at libero.it"<giacsport at libero.it>, "PWSCF
> >Forum"<pw_forum at pwscf.
>
> org>
>
> >Ogg: Re: [Pw_forum] HSE vs PBE
> >
> >
> >Dear Giacomo
> >
> >> is it OK? can I do it? I.e., using PBE psudopotential for HSE
> >> calculations?
> >
> >A the present time, there is no other way to perform hybrid calculations
> >but
>
> with GGA (norm
>
> >conserving) pseudopotentials. In this regard, I suppose that a 95 Ry wfc
>
> cutoff may be poor for
>
> >copper (with semicore 3s and 3p). You should test the convergence of your
> >PBE
>
> results before
>
> >attempting HSE calculations.
> >
> >> and then use the same for HSE (same pseudopotentials at PBE, taken from
> >> the PwSCF website)
> >
> >I'm quite puzzled... There is no NC pseudopotential for copper in the
>
> website. Do you mean the
>
> >pslibrary?
> >
> >> input_dft='hse', nqx1= 2, nqx2= 2, nqx3= 2,
> >
> >You should check the convergence of your results wrt the blend of k points
>
> and q points, and this is
>
> >the most painful task when using hybrid functionals (and metals are very
>
> sensitive to k points...).
>
> >In practice, be sure to the convergence of k points in the PBE
> >calculation,
>
> and starting from
>
> >nqx1= 1, nqx2= 1, nqx3= 1,
> >
> >try to reach convergence (or reach the most bloody-cpu-consuming grid you
> >can
>
> afford) wrt the q
>
> >points.
> >
> >> nspin=2
> >
> >Copper is nonmagnetic, and you have an even number of atoms. Save (a lot
> >of)
>
> time with nspin=1.
>
> >> nbnd = 80
> >> occupations='smearing'
> >
> >The latter provide already a fair number of unoccupied states, you do not
>
> need to use the former.
>
> >HTH
> >
> >Giuseppe
> >
> >On Thursday 24 May 2012 04:45:14 giacsport at libero.it wrote:
> >> Dear All,
> >>
> >> I am using the development version of PWscf.
> >>
> >> I would like to ask you this question.
> >>
> >> I want to make HSE hybrid calculations (vc-relax) using pseudopotential
> >> at PBE level.
> >> I want indeed test the impact of the hybrid functional in the lattice
> >> parameter (this is the case of Copper)
> >>
> >> I mean is it a correct procedure to optimize the system with such
> >> initial settings
> >>
> >> /
> >> &system
> >>
> >> ibrav= 2, celldm(1) = 6.830792531
> >> nat= 4, ntyp= 1, nspin=2,
> >> ecutwfc = 95., nbnd = 80, occupations='smearing',
> >> degauss=0.01,smearing='gaussian', starting_magnetization(1)=1
> >>
> >> /
> >>
> >> and then use the same for HSE (same pseudopotentials at PBE, taken from
> >> the PwSCF website)
> >>
> >> /
> >> &system
> >>
> >> ibrav= 2, celldm(1) = 6.830792531
> >> nat= 4, ntyp= 1, nspin=2,
> >> ecutwfc = 95., nbnd = 80, occupations='smearing',
> >> degauss=0.01,smearing='gaussian', starting_magnetization(1)=1
> >> input_dft='hse', nqx1= 2, nqx2= 2, nqx3= 2,
> >> x_gamma_extrapolation = .TRUE.
> >>
> >> /
> >>
> >> is it OK? can I do it? I.e., using PBE psudopotential for HSE
> >> calculations?
> >>
> >>
> >> Thanks in advance for any suggestion!
> >>
> >> Best,
> >> Giacomo
>
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Giuseppe Mattioli
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