maybe you’re visualising the conventional, rather than the primitive unit cell. Try to set Display -> Primitive Cell Mode
The bct unit cel should show up. Giovanni -- Giovanni Cantele, PhD CNR-SPIN c/o Dipartimento di Fisica Universita' di Napoli "Federico II" Complesso Universitario M. S. Angelo - Ed. 6 Via Cintia, I-80126, Napoli, Italy e-mail: giovanni.cant...@spin.cnr.it gcant...@gmail.com Phone: +39 081 676910 Skype contact: giocan74 Web page: https://sites.google.com/view/giovanni-cantele > On 19 Nov 2018, at 19:38, Chan, Edmund <thc...@exeter.ac.uk> wrote: > > Dear all users, > > I am currently trying to relax a methylammonium lead iodide CH3NH3PbI3 > structure which has tetragonal structure I4/mcm. Thus, in my input file, I > select ibrav = 7 (body centred teragonal). However, as I visualise the input > and output on Xcrysden, the unit cell becomes orthorhombic. Why is that? > > > &CONTROL > title = 'MAPI' , > calculation = 'relax' , > restart_mode = 'from_scratch' , > outdir = './' , > pseudo_dir = './' , > prefix = 'CH3NH3PbI3' , > / > &SYSTEM > ibrav = 7, > A = 8.83920, > C = 12.6948, > nat = 12, > ntyp = 5, > ecutwfc = 80 , > ecutrho = 800, > / > &ELECTRONS > electron_maxstep = 5000 , > conv_thr = 1.0d-6 , > mixing_beta = 0.3 , > / > &IONS > ion_dynamics = 'bfgs' , > / > ATOMIC_SPECIES > C 12.01070 c_pbesol_v1.2.uspp.F.UPF > H 1.00794 H.pbesol-rrkjus_psl.0.1.UPF > N 14.00670 N.pbesol-theos.UPF > Pb 207.20000 Pb.pbesol-dn-kjpaw_psl.0.2.2.UPF > I 126.90450 i_pbesol_v1.uspp.F.UPF > ATOMIC_POSITIONS alat > Pb 0.000000000 0.000000000 0.500000000 > I 0.000000000 0.000000000 0.250000000 > I 0.294200000 0.205800000 0.500000000 > I -0.294200000 -0.207600000 0.500000000 > C 0.544000000 0.921000000 0.784000000 > H 0.609200000 1.002100000 0.769900000 > H 0.557300000 0.845500000 0.724600000 > H 0.551500000 0.875200000 0.864300000 > N 0.389000000 0.987000000 0.767000000 > H 0.324700000 0.913900000 0.730300000 > H 0.381400000 1.068100000 0.734300000 > H 0.339300000 0.990800000 0.831000000 > K_POINTS automatic > 1 1 1 0 0 0 > > Thank you all. > > > Kind regards, > > Edmund Chan > ________________________________________________ > Edmund Chan > PhD Renewable Energy Student > Environment & Sustainablity Institute > College of Engineering, Mathematics and Physical Sciences > University of Exeter, Penryn Campus > Penryn, Cornwall > United Kingdom > TR10 9FE > > Tel: +44 (0)7455 235 701 <tel:+44%207455%20235%20701> > Email: thc...@exeter.ac.uk <mailto:thc...@exeter.ac.uk> > LinkedIn: https://uk.linkedin.com/in/edmundchan1 > <https://uk.linkedin.com/in/edmundchan1> > <image002.jpg> > > <image003.gif> > > _______________________________________________ > users mailing list > users@lists.quantum-espresso.org <mailto:users@lists.quantum-espresso.org> > https://lists.quantum-espresso.org/mailman/listinfo/users > <https://lists.quantum-espresso.org/mailman/listinfo/users>
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