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 <lorechimic...@hotmail.it> 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 <davide.ti...@epfl.ch> >> 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? <lorechimic...@hotmail.it> >> Subject: [Pw_forum] CPO-27-Zn scf not converge >> To: PWSCF Forum <pw_forum@pwscf.org> >> Message-ID: <blu436-smtp367637bd78842fca03b145cb...@phx.gbl> >> 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 >> Pw_forum@pwscf.org >> http://pwscf.org/mailman/listinfo/pw_forum > > _______________________________________________ > Pw_forum mailing list > Pw_forum@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@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum