Dear QE Friends: I encounter a problem with the space_group option. A part of my QE input is attached at the end of this message.
The crystal I am working on has symmetry "C 1 2/c 1" (as suggested by the cif file from which I take the structure data). Suggested by the following two webpages, I set "space_group = 15". http://www.cryst.ehu.es/cgi-bin/cryst/programs/nph-wp-list?gnum=15&gua=b http://img.chem.ucl.ac.uk/sgp/large/015ay1.htm Because the unique axis is along b in my problem, I take "ibrav = -12" (monoclinic). Running QE, I got the following error message. Error in routine input (1): Input ibrav not compatible with space group number There is not much information about space_group option in QE manual. Could ould you please point out what is wrong with the input? Thbak you. Tsung-Lung Li --------------------------------------------------- &system ibrav = -12 celldm(1) = 11.86181088389489 ! bohr ntyp = 4 nat = 7 space_group = 15 uniqueb = .true. origin_choice = 1 .... / ATOMIC_SPECIES Ca 40.0780000000 Ca_pbe_v1.uspp.F.UPF S 32.0650000000 S_pbe_v1.2.uspp.F.UPF O 15.9994000000 O.pbe-n-kjpaw_psl.0.1.UPF H 1.0079000000 H.pbe-rrkjus_psl.0.1.UPF ATOMIC_POSITIONS crystal_sg Ca 0.00000 0.17050 0.25000 S 0.00000 0.32727 0.75000 O 0.08319 0.27218 0.59103 O 0.19997 0.38195 0.91298 O -0.20823 0.06826 -0.07831 H -0.25800 0.08700 -0.23400 H -0.24400 0.02000 -0.07700 -- _______________________________________________ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum