[Pw_forum] Construction of PtH structure, wrong pointgroup problem

[Bahadir Altintas]

Hi,
I have a problem in constructing the PtH structure.
I have prepared the input with following data from J. Phys. Chem. C, 
2012, 116 (2), pp 1995--2000 
(http://http://pubs.acs.org/doi/abs/10.1021%2Fjp210780m) for hexagonal PtH.

Spacegroup : 194 - P63/mmc
Point group : D_6h
a=2.795
c=7.769
Pt: 2c (1/3 2/3 0.25)
H: 2a ( 0 0 0 )

Point group of this input  gives  D_3d (-3m) instead of D_6h (6/mmm). I 
am not sure what am i missing.

here is my input for vc-relax under 100GPa (Espresso-4.3.2):

&CONTROL
     calculation =   "vc-relax"   ,
     restart_mode = 'from_scratch' ,
     outdir='/tmp' ,
     pseudo_dir ='/home/pseudos/espresso/' ,
     etot_conv_thr = 1.0D-14  ,
     forc_conv_thr = 1.0D-5 ,
     prefix='PtH_sp194_100GPa.opt',
     tstress=.true.,
  verbosity='high'
   /
&SYSTEM
      ibrav= 4,
      celldm(1)=5.2817842823,
      celldm(3)=1.706261153,
      nat= 4,
      ntyp= 2,
                      ecutwfc=37
                   ecutrho  =  222 ,
                   occupations  =  'smearing' ,
                      smearing  =  'mp' ,
                       degauss  =  0.02 ,
  /
&ELECTRONS
    conv_thr  =  1.0d-7,
   diagonalization='david'
   /
&IONS
   ion_dynamics = 'bfgs',
   /
&CELL
     cell_dynamics = 'bfgs' ,
     cell_factor=1.2,
      press= 1000.00
   /

  ATOMIC_SPECIES
  Pt  195.08 Pt.pbe-n-van.UPF
  H  1.00794 H.pbe-van_ak.UPF

  ATOMIC_POSITIONS (crystal)
  Pt       0.333333343   0.666666687   0.250000438
  Pt       0.666666627   0.333333313   0.749999562
  H        0.000000000   0.000000000   0.000000000
  H        0.000000000   0.000000000   0.500000000

  K_POINTS automatic
  4 4 4 1 1 1





Thanks,

Bahadir Altintas
University at Buffalo
Dept of Chemistry
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20120522/e519d3f8/attachment.html>