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 -- ******************************************************** - Article premier - Les hommes naissent et demeurent libres et ?gaux en droits. Les distinctions sociales ne peuvent ?tre fond?es que sur l'utilit? commune - Article 2 - Le but de toute association politique est la conservation des droits naturels et imprescriptibles de l'homme. Ces droits sont la libert?, la propri?t?, la s?ret? et la r?sistance ? l'oppression. ******************************************************** Giuseppe Mattioli CNR - ISTITUTO DI STRUTTURA DELLA MATERIA v. Salaria Km 29,300 - C.P. 10 I 00015 - Monterotondo Stazione (RM) Tel + 39 06 90672836 - Fax +39 06 90672316 E-mail: <giuseppe.mattioli at ism.cnr.it>
