You need: - the space group number - the cell parameters (for the rhombohedral lattice, not the hexagonal one) - the Wyckoff positions. If the latter are given in hexagonal axis, as they are here: http://www.cryst.ehu.es/cgi-bin/cryst/programs/nph-wp-list use "rhombohedral=.false." This is all I know about the specific case of rhombohedral groups
Paolo On Sat, Jun 4, 2016 at 8:01 PM, Lorenzo Donà <[email protected]> wrote: > Dear Paolo I have tried a lot of inputs with space_group=148 keyword but the > structure found is incorrect… > Or better is correct the number of atom 54 in the cell but the position is > incorrect. > Please can you help me to understand the correct input for my system, can > you tell me how to create the correct structure input using the keyword > space_group. > I must tell you that i found problem only for this system for cubic or > ORTHORHOMBIC system I found NO problem. > Thanks a lot if you can help me with my problem. > Dearly > lorenzo > > Il giorno 31 mag 2016, alle ore 21:58, Paolo Giannozzi > <[email protected]> ha scritto: > > For the rhombohedral (or trigonal) trigonal lattice, cosab=-0.5 means > that the angle between any two of the three primitive vectors is 120, > that is, they lie on a plane. This is why the code complains. By the > way, here a converter between rhombohedral and hexagonal cells: > http://qpeng.org/tools/r2h.html, and here a picture (fig.5): > http://xrayweb.chem.ou.edu/notes/symmetry.html > > > On Tue, May 31, 2016 at 9:57 AM, Lori 91 <[email protected]> wrote: > > Thanks to replay Davide. > cosab=-0.5 give me an error. > Thanks a lot dearly > Lorenzo > > Inviato da iPhone > > Il giorno 31 mag 2016, alle ore 09:16, Tiana Davide <[email protected]> > ha scritto: > > Ciao Lorenzo > > I am not sure but one problem could be that you're using cosab 0.5 (60 > degrees) instead of cosab=-0.5 (120 degrees) > another one (again just a guess) is your cut-off seems to be really low even > for an ultrasoft pseudopotential. > > anyway, you should try with this electron setting > > mixing_mode='local-TF', > mixing_beta=0.6, > > I've not problem in converging it (using different pseudo though) > > Cheers > Davide > > P.S. the last test you can do is to use a bit of smearing, for instance: > > occupations='smearing', > smearing='marzari-vanderbilt' > degauss=0.05 > ________________________________________ > ------------------------------ > > Message: 2 > Date: Sun, 29 May 2016 21:11:49 +0200 > From: Lorenzo Don? <[email protected]> > Subject: [Pw_forum] CPO-27-Zn scf not converge > To: PWSCF Forum <[email protected]> > Message-ID: <[email protected]> > Content-Type: text/plain; charset="us-ascii" > > Dear all can you help me or give me some tips to make scf convergence on > this calculation: > > &control > pseudo_dir='/home/utente/Scaricati/espresso-5.4.0/pseudo/' > outdir = './', > wf_collect = .true., > verbosity= high, > / > &system > ibrav= 5, > a= 25.226, cosab= 0.5, space_group = 148, > nat= 9, ntyp= 4, > ecutwfc =15.0, > occupations='fixed', smearing='gauss', > input_dft= PBE, > / > &electrons > mixing_mode='plain' > diagonalization='david' > mixing_beta = 0.01 > conv_thr= 1.0e-4 > electron_maxstep=500, > / > ATOMIC_SPECIES > Zn 65.409 Zn.pbe-van.UPF > C 12.010 C.pbe-van_ak.UPF > O 16.00 O.pbe-van_ak.UPF > H 1.00 H.pbe-van_ak.UPF > ATOMIC_POSITIONS crystal_sg > C 7.127430447398E-02 -2.455696438145E-01 7.991093030472E-02 > C 1.197468901477E-01 -2.066445045066E-01 2.152449225957E-01 > C 2.117353032357E-01 -1.117780631842E-01 2.553368090727E-01 > C 1.646071563067E-01 -1.528403540257E-01 1.440875844425E-01 > H 1.629458066146E-01 -1.419696182443E-01 -4.760745519579E-03 > Zn -1.943259345214E-02 2.834354147594E-01 3.060064447988E-01 > O 7.229455751443E-02 -2.290060932141E-01 -9.085450716092E-02 > O 3.018234203718E-02 -2.947952345384E-01 1.422041978763E-01 > O 2.519030126218E-01 -6.097111538485E-02 1.721974260943E-01 > K_POINTS gamma > > Thanks a lot to help me > > dearly > > lorenzo > > > > _______________________________________________ > > _______________________________________________ > 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 > > > > _______________________________________________ > 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
