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Hi,<br>
I have a problem in constructing the PtH structure. <br>
I have prepared the input with following data from <cite>J. Phys.
Chem. C</cite>, <span class="citation_year">2012</span>, <span
class="citation_volume">116</span> (2), pp 1995–2000
(<a class="moz-txt-link-freetext" href="http://http://pubs.acs.org/doi/abs/10.1021%2Fjp210780m">http://http://pubs.acs.org/doi/abs/10.1021%2Fjp210780m</a>) for
hexagonal PtH.<br>
<br>
Spacegroup : 194 - P63/mmc <br>
Point group : D_6h<br>
a=2.795<br>
c=7.769<br>
Pt: 2c (1/3 2/3 0.25)<br>
H: 2a ( 0 0 0 )<br>
<br>
Point group of this input gives D_3d (-3m) instead of D_6h
(6/mmm). I am not sure what am i missing.<br>
<br>
here is my input for vc-relax under 100GPa (Espresso-4.3.2):<br>
<br>
&CONTROL<br>
calculation = "vc-relax" ,<br>
restart_mode = 'from_scratch' ,<br>
outdir='/tmp' ,<br>
pseudo_dir ='/home/pseudos/espresso/' ,<br>
etot_conv_thr = 1.0D-14 ,<br>
forc_conv_thr = 1.0D-5 ,<br>
prefix='PtH_sp194_100GPa.opt',<br>
tstress=.true.,<br>
verbosity='high'<br>
/<br>
&SYSTEM<br>
ibrav= 4,<br>
celldm(1)=5.2817842823,<br>
celldm(3)=1.706261153,<br>
nat= 4,<br>
ntyp= 2,<br>
ecutwfc=37<br>
ecutrho = 222 ,<br>
occupations = 'smearing' ,<br>
smearing = 'mp' ,<br>
degauss = 0.02 ,<br>
/<br>
&ELECTRONS<br>
conv_thr = 1.0d-7,<br>
diagonalization='david'<br>
/<br>
&IONS<br>
ion_dynamics = 'bfgs',<br>
/<br>
&CELL<br>
cell_dynamics = 'bfgs' ,<br>
cell_factor=1.2,<br>
press= 1000.00<br>
/<br>
<br>
ATOMIC_SPECIES<br>
Pt 195.08 Pt.pbe-n-van.UPF<br>
H 1.00794 H.pbe-van_ak.UPF<br>
<br>
ATOMIC_POSITIONS (crystal)<br>
Pt 0.333333343 0.666666687 0.250000438<br>
Pt 0.666666627 0.333333313 0.749999562<br>
H 0.000000000 0.000000000 0.000000000<br>
H 0.000000000 0.000000000 0.500000000<br>
<br>
K_POINTS automatic<br>
4 4 4 1 1 1<br>
<br>
<br>
<br>
<br>
<br>
Thanks,<br>
<br>
Bahadir Altintas<br>
University at Buffalo<br>
Dept of Chemistry<br>
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