Dear Paolo:

Thank you for your response.

I change the input according to your suggestion.
The QE code runs but produces results that may not
be correct.

The complete QE input and part of output are
attached by the end of this message.

The crystal is determined by QE to be "ibrav=-13"
(see the output), which is an undocumented feature
in QE 5.3.0.  (I assume it is like "ibrav=13" with
a different unqiue axis.)

The cif file from which I took the structure data
shows that the crystal has symmetry "C 1 2/c 1"
(monoclinic P) with unique axis along b, which should
correspond to "ibrav=-12" rather than "ibrav=13".

By the way, I also used cif2qe.sh to convert the
cif file to QE input, the results are correct.
The cif file is attached at the very end of this
message.

Could you please point out if I make a mistake
in the input?

Thank you very much. I truly appeciate your work.


Tsung-Lung Li

------------------------------------------------------
QE input file
------------------------------------------------------
&control
  title = 'Gypsum (CaSO4.2H20 Z=4)'
  prefix = 's-12'
  outdir = '/work2/u2equa02/tempdir/s-12'
  pseudo_dir = '/home/u2equa02/quantumhome/pseudo'
  calculation = 'scf'
  restart_mode = 'from_scratch'
  disk_io = 'low'
  verbosity = 'high'
  wf_collect = .true.
  tstress = .true.
  tprnfor = .true.
  etot_conv_thr = 1.0D-4
  forc_conv_thr = 1.0D-3
/
&system
  celldm(1) = 11.86181088389489 ! bohr
  celldm(2) = 2.41851202803887
  celldm(3) = 0.903616377250276
  celldm(5) = -0.408489773780522
  ntyp = 4
  nat = 7
  space_group = 15
  uniqueb = .true.
  origin_choice = 1
  ecutwfc = 10
  ecutrho = 80
/
&electrons
  electron_maxstep = 200
  conv_thr = 1.0D-6
  startingpot = 'atomic'
  startingwfc = 'atomic+random'
  mixing_mode = 'plain'
  mixing_beta = 0.5
  mixing_ndim= 8
  diagonalization = 'david'
/
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

K_POINTS automatic
2 1 2 0 0 0

------------------------------------------------------
QE output file (partial)
------------------------------------------------------
     bravais-lattice index     =          -13
     lattice parameter (alat)  =      11.8618  a.u.
     unit-cell volume          =    1664.6131 (a.u.)^3
     number of atoms/cell      =           24
     number of atomic types    =            4
     number of electrons       =       112.00
     number of Kohn-Sham states=           56
     kinetic-energy cutoff     =      10.0000  Ry
     charge density cutoff     =      80.0000  Ry
     convergence threshold     =      1.0E-06
     mixing beta               =       0.5000
     number of iterations used =            8  plain     mixing
     Exchange-correlation      = PBE ( 1  4  3  4 0 0)

     celldm(1)=  11.861811  celldm(2)=   2.418512  celldm(3)=   0.903616
     celldm(4)=   0.000000  celldm(5)=  -0.408490  celldm(6)=   0.000000

     crystal axes: (cart. coord. in units of alat)
               a(1) = (   0.500000  -1.209256   0.000000 )
               a(2) = (   0.500000   1.209256   0.000000 )
               a(3) = (  -0.369118   0.000000   0.824788 )

     reciprocal axes: (cart. coord. in units 2 pi/alat)
               b(1) = (  1.000000 -0.413477  0.447531 )
               b(2) = (  1.000000  0.413477  0.447531 )
               b(3) = (  0.000000  0.000000  1.212434 )

------------------------------------------------------
cif file
------------------------------------------------------
data_global
_chemical_name_mineral 'Gypsum'
loop_
_publ_author_name
'Comodi P'
'Nazzareni S'
'Zanazzi P F'
'Speziale S'
_journal_name_full 'American Mineralogist'
_journal_volume 93
_journal_year 2008
_journal_page_first 1530
_journal_page_last 1537
_publ_section_title
;
 High-pressure behavior of gypsum: A single-crystal X-ray study
 Note: P = 0.0001 GPa
;
_database_code_amcsd 0004651
_chemical_compound_source 'Valle di Caramanico, Abruzzo, Italy'
_chemical_formula_sum 'Ca S O6 H4'
_cell_length_a 6.277
_cell_length_b 15.181
_cell_length_c 5.672
_cell_angle_alpha 90
_cell_angle_beta 114.11
_cell_angle_gamma 90
_cell_volume 493.340
_exptl_crystal_density_diffrn      2.318
_symmetry_space_group_name_H-M 'C 1 2/c 1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '1/2+x,1/2+y,z'
  'x,-y,1/2+z'
  '1/2+x,1/2-y,1/2+z'
  '-x,y,1/2-z'
  '1/2-x,1/2+y,1/2-z'
  '-x,-y,-z'
  '1/2-x,1/2-y,-z'
loop_
_atom_site_type_symbol
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_U_iso_or_equiv
Ca   0.00000   0.17050   0.25000   0.01170
S   0.00000   0.32727   0.75000   0.00990
O   0.08319   0.27218   0.59103   0.01690
O   0.19997   0.38195   0.91298   0.01690
O  -0.20823   0.06826  -0.07831   0.02410
H  -0.25800   0.08700  -0.23400   0.03300
H  -0.24400   0.02000  -0.07700   0.04400


On 10/13/2016 09:35 PM, Paolo Giannozzi wrote:
I don't think you need to specify "ibrav" (the code should selecvt the proper one), but you need to specify celldm(2) and celldm(3).

Paolo

On Thu, Oct 13, 2016 at 2:39 PM, Tsung-Lung Li <quan...@mail.ncyu.edu.tw <mailto:quan...@mail.ncyu.edu.tw>> wrote:

    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://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
    <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

    --

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--
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



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--
Tsung-Lung Li, Ph. D.
Professor
Department of Electrophysics
National Chia-Yi University
300 Hsueh-Fu Road, Chiayi 60004, Taiwan
Phone: 886-5-2717904.  FAX: 886-5-2717909.
E-mail:quan...@mail.ncyu.edu.tw

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