[QE-users] TB09, TPSS

[Stefano Baroni]

A possibility would be to hack the functional, and gradually “switch on” the TB09 functional starting from PBE: something like FUNCT[alpha] = alpha*TB09 + (1-alpha)PBE, but this, of course, requires some coding … SB

> On 21 May 2020, at 08:46, Paolo Giannozzi <p.giannozzi at gmail.com> wrote:
> 
> On Wed, May 20, 2020 at 9:34 PM Michal Krompiec <michal.krompiec at gmail.com <mailto:michal.krompiec at gmail.com>> wrote:
> I changed io_rho_xml.f90 so that if the kinetic energy density file isn't found, the array is set to 0:
> [...]
> Now I can start a TB09 calculation from a PBE density, but still my test case diverges immediately (...)
> I would be very grateful for any suggestions.
> 
> unfortunately I haven't any. 
> 
> Paolo
> 
> Best,
> Michal
> 
> P.S. This is my input file:
> &CONTROL
>     calculation  = "scf"
>     prefix       = "sic"
> /
> 
> &SYSTEM
>     a           =  4.34800e+00
>     ibrav       = 1
>    ecutwfc          = 82
>    ecutrho          = 328
>     nat         = 8
>     ntyp        = 2
>     occupations = "fixed"
> input_dft='tb09'
> /
> &ELECTRONS
>    electron_maxstep = 1000
>    conv_thr         = 1e-10
>    mixing_mode      = 'plain'
>    mixing_beta      = 0.4
>   startingpot = 'file'
>   startingwfc = 'file'
>   diagonalization = 'cg'
> /
> 
> K_POINTS automatic
> 8 8 8   1 1 1
> 
> ATOMIC_SPECIES
> Si     28.08500  Si.upf
> C      12.01060  C.upf
> 
> 
> ATOMIC_POSITIONS {angstrom}
> Si      0.000000   0.000000   0.000000
> Si      0.000000   2.174000   2.174000
> Si      2.174000   0.000000   2.174000
> Si      2.174000   2.174000   0.000000
> C       1.087000   1.087000   1.087000
> C       1.087000   3.261000   3.261000
> C       3.261000   1.087000   3.261000
> C       3.261000   3.261000   1.087000
> 
> On Fri, 8 May 2020 at 09:39, Paolo Giannozzi <p.giannozzi at gmail.com <mailto:p.giannozzi at gmail.com>> wrote:
> >
> > On Thu, May 7, 2020 at 10:33 PM Michal Krompiec <michal.krompiec at gmail.com <mailto:michal.krompiec at gmail.com>> wrote:
> >
> >>
> >>  it was suggested to start from a density calculated with a different functional, but when I try to read in PBE density, it complains that it cannot read the kinetic energy file (which obviously cannot be there).
> >
> >
> > this can be easily changed, I think: just disable the check and set the kinetic energy density to zero
> >
> >>
> >> Should TPSS or SCAN pseudos work better (and where do I get them from)?
> >
> >
> > I don't think the problem is in the pseudos but in the nasty numerical behavior of meta-GGAs. See for instance here: https://gitlab.com/QEF/q-e/-/issues/32 <https://gitlab.com/QEF/q-e/-/issues/32>. Note that several bugs have been fixed in the development version.
> >
> > Paolo
> >
> >> Thanks,
> >> Michal Krompiec
> >> Merck KGaA
> >>
> >> _______________________________________________
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> >
> >
> >
> > --
> > Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
> > Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> > Phone +39-0432-558216, fax +39-0432-558222
> >
> > _______________________________________________
> > Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso <http://www.max-centre.eu/quantum-espresso>)
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> _______________________________________________
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso <http://www.max-centre.eu/quantum-espresso>)
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> 
> 
> -- 
> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
> 
> _______________________________________________
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso)
> users mailing list users at lists.quantum-espresso.org
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— 
Stefano Baroni - Trieste —  http://stefano.baroni.me <http://stefano.baroni.me/> 




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