[Pw_forum] vc-relax cell parameters are not changing
Isaiah Moses
imoses87 at gmail.com
Fri Jun 23 12:30:33 CEST 2017
Ok,
My question concerns your comment that "One should use instead
CELL_PARAMETERS (angstrom)
to specify lattice vectors in A" where as what I obtain in vc-relax output
is
CELL_PARAMETERS (alat= 8.11400000).
So, I am wondering if there is a particular way I ought to define my
celldm(1) or any other parameter in other to obtain output in the format
CELL_PARAMETERS (angstrom).
Thanks a lot for your help,
Isaiah
On Fri, Jun 23, 2017 at 11:16 AM, Paolo Giannozzi <p.giannozzi at gmail.com>
wrote:
> I don't remember what the code prints during a vc-relax calculation,
> but I know for sure that the output of ATOMIC_POSITIONS and
> CELL_PARAMETERS is in a format that can be used as input.
>
> On Fri, Jun 23, 2017 at 8:30 AM, Isaiah Moses <imoses87 at gmail.com> wrote:
> > Hi Paolo,
> > But how does one set CELL_PARAMETERS (angstrom)?
> > Because I observe that the output I obtain from vc-relax is automatically
> > set to
> > CELL_PARAMETERS (alat= 8.11400000).
> > Does that has to do with the unit of celldm?
> >
> > I must be missing something on theses units' usage.
> >
> > I appreciate your usual prompt response,
> > Isaiah
> >
> > On Fri, Jun 23, 2017 at 7:16 AM, Paolo Giannozzi <p.giannozzi at gmail.com>
> > wrote:
> >>
> >> And, by the way, it is a bad habit to set the lattice parameter to the
> >> conversion factor between a.u. and A. One should use instead
> >> CELL_PARAMETERS (angstrom)
> >> to specify lattice vectors in A
> >>
> >> Paolo
> >>
> >> On Fri, Jun 23, 2017 at 4:55 AM, Stefano de Gironcoli <
> degironc at sissa.it>
> >> wrote:
> >> > The lattice parameter does not change, it is not updated along
> vc-relax,
> >> > the
> >> > lattice vectors do.
> >> > Using bfgs you don't need to define dt
> >> >
> >> > stefano
> >> > (sent from my phone)
> >> >
> >> > On 23 Jun 2017, at 01:55, Brendan Smith <mrbsmith58 at gmail.com> wrote:
> >> >
> >> > Hello all,
> >> >
> >> > I am doing a the following vc-relax calculation and the unit cell
> >> > paramters
> >> > are not changing. I have looked at other posts which descirbes similar
> >> > problems, but it does not remedy my problem. Below is my input.
> >> > Best,
> >> > Brendan
> >> >
> >> >
> >> > &CONTROL
> >> > calculation = 'vc-relax',
> >> > dt = 20.67055,
> >> > nstep = 1000,
> >> > pseudo_dir = './'
> >> > outdir = './',
> >> > prefix = 'x',
> >> > disk_io = 'low',
> >> > /
> >> >
> >> > &SYSTEM
> >> > ibrav = 0,
> >> > celldm(1) = 1.89,
> >> > nat = 16,
> >> > ntyp = 3,
> >> > nspin = 1,
> >> > nbnd = 120,
> >> > ecutwfc = 70,
> >> > ecutrho = 560,
> >> > tot_charge = 0.0,
> >> > occupations = 'smearing',
> >> > smearing = 'gaussian',
> >> > degauss = 0.005,
> >> > nosym = .true.,
> >> > /
> >> >
> >> > &ELECTRONS
> >> > electron_maxstep = 1000,
> >> > conv_thr = 1.D-5,
> >> > mixing_beta = 0.45,
> >> > /
> >> >
> >> > &IONS
> >> > ion_dynamics = 'bfgs',
> >> > ion_temperature = 'andersen',
> >> > tempw = 300.00 ,
> >> > nraise = 1,
> >> > /
> >> >
> >> > &CELL
> >> > cell_dynamics = 'bfgs',
> >> > press_conv_thr = 0.5,
> >> > cell_factor = 2.0,
> >> > cell_dofree = 'all',
> >> > /
> >> >
> >> > ATOMIC_SPECIES
> >> > O 15.9994 O_pbe_v1.2.uspp.F.UPF
> >> > V 50.9415 V_pbe_v1.uspp.F.UPF
> >> > Pb 207.2 Pb.pbe-dn-rrkjus_psl.0.2.2.UPF
> >> >
> >> > K_POINTS automatic
> >> > 3 3 3 0 0 0
> >> >
> >> > CELL_PARAMETERS (alat)
> >> > 11.5439996719 0.0000000000 0.0000000000
> >> > 0.0000000000 3.5710000992 0.0000000000
> >> > 0.0000000000 0.0000000000 4.3829998970
> >> >
> >> > ATOMIC_POSITIONS (alat)
> >> > V 6.940599 0.892750 0.475994
> >> > V 4.603400 2.678250 3.907006
> >> > V 10.375401 0.892750 0.475994
> >> > V 1.168599 2.678250 3.907006
> >> > O 4.974309 0.892750 4.370728
> >> > O 6.569691 2.678250 0.012272
> >> > O 0.797690 0.892750 4.370728
> >> > O 10.746309 2.678250 0.012272
> >> > O 6.978348 0.892750 2.058695
> >> > O 4.565652 2.678250 2.324305
> >> > O 10.337652 0.892750 2.058695
> >> > O 1.206349 2.678250 2.324305
> >> > O 8.658000 0.892750 0.003506
> >> > O 2.886000 2.678250 4.379493
> >> > Pb 8.500000 2.500000 1.500000
> >> > Pb 3.000000 1.500000 3.000000
> >> >
> >> >
> >> >
> >> >
> >> > _______________________________________________
> >> > Pw_forum mailing list
> >> > Pw_forum at pwscf.org
> >> > http://pwscf.org/mailman/listinfo/pw_forum
> >> >
> >> >
> >> > _______________________________________________
> >> > Pw_forum mailing list
> >> > Pw_forum at pwscf.org
> >> > http://pwscf.org/mailman/listinfo/pw_forum
> >>
> >>
> >>
> >> --
> >> 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
> >> _______________________________________________
> >> Pw_forum mailing list
> >> Pw_forum at pwscf.org
> >> http://pwscf.org/mailman/listinfo/pw_forum
> >
> >
> >
> >
> > --
> > Isaiah Abu Moses
> > Graduate Student,
> > Physics Department,
> > University of Ibadan,
> > Nigeria
> >
> > _______________________________________________
> > Pw_forum mailing list
> > Pw_forum at pwscf.org
> > http://pwscf.org/mailman/listinfo/pw_forum
>
>
>
> --
> 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
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum
>
--
Isaiah Abu Moses
Graduate Student,
Physics Department,
University of Ibadan,
Nigeria
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20170623/a7c0c534/attachment.html>
More information about the users
mailing list