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 <[email protected]> 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 <[email protected]> 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 <[email protected]> > > 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 < > [email protected]> > >> 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 <[email protected]> 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 > >> > [email protected] > >> > http://pwscf.org/mailman/listinfo/pw_forum > >> > > >> > > >> > _______________________________________________ > >> > Pw_forum mailing list > >> > [email protected] > >> > 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 > >> [email protected] > >> http://pwscf.org/mailman/listinfo/pw_forum > > > > > > > > > > -- > > Isaiah Abu Moses > > Graduate Student, > > Physics Department, > > University of Ibadan, > > Nigeria > > > > _______________________________________________ > > Pw_forum mailing list > > [email protected] > > 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 > [email protected] > http://pwscf.org/mailman/listinfo/pw_forum > -- Isaiah Abu Moses Graduate Student, Physics Department, University of Ibadan, Nigeria
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