[Pw_forum] is it orthorhombic or triclinic?

Krishna chaitanya krishnachaitanya.gunturu at gmail.com
Wed Mar 6 09:50:48 CET 2013


Dear users....

I am trying to get optimized geometry of  (201) plane of Bi2O3 with three
layers. When I cleaved the tetragonal geometry of Bi2O3 crystal through
(201) plane, Material Studio software is showing it as triclinic geometry
with lattice constants a=13.8295, b=15.4760, c=34.1069 (of which
20angstroms is vacuum), alpha=beta=gamma=90 degrees. But according to
crystallographic systems, these constants should belong to orthorhombic
rather than triclinic. Then how Material studio is showing it as triclinic?

I am declaring it as triclinic by using ibrav=14 in $SYSTEM section. Is
there any wrong in that? Is that the reason why I am not able to get SCF
convergence. My input is given below. Please suggest me in this regard.

&CONTROL
  calculation = "relax",
  pseudo_dir     = "/home/scs1/pwscf/espresso-5.0-GPU/pseudo",
  title       = "bi2o3-bare-uspp",
  prefix      = "bi2o3-bare-uspp",
  verbosity   = "high",
  outdir      = "/home/scs1/tmp",
  wfcdir      = "/home/scs1/tmp",
  nstep       = 300,
  etot_conv_thr = 1.0D-2,
  forc_conv_thr = 1.0D-2,
  disk_io     = "high",
/
&SYSTEM
  ibrav = 14,
  A=13.8295,
  B=15.4760,
  C=34.1069,
  COSAB=0,
  COSAC=0,
  COSBC=0,
  nat = 120,
  ntyp = 2,
  ecutwfc = 40,
  ecutrho= 280,
/
&ELECTRONS
  electron_maxstep = 500,
  diago_david_ndim = 2,
  mixing_beta = 0.1,
  mixing_mode = 'local-TF',
  conv_thr = 1.0D-3,
/
$IONS
/
 ATOMIC_SPECIES
 Bi 208.98  bi_ps-formatted.vdb
 O  16.000   O.pbe-van_bm.UPF
ATOMIC_POSITIONS angstrom
  Bi      6.2327     7.1388     2.1416
  Bi      1.4827     7.1388     5.3483
  Bi     10.5623     7.1388     8.5550
  O     13.1281     7.6348     0.0000
  O      8.3780     7.6348     3.2067
  O      3.6282     7.6348     6.4135
  Bi      6.0525     3.1785     1.8749
  Bi      1.3026     3.1785     5.0816
  Bi     10.3822     3.1785     8.2883
   O       1.1170     2.6825     2.6938
   O      10.1965     2.6825     5.9002
   O       5.4466     2.6825     9.1069
   Bi       9.4953     4.9977     2.1341
   Bi       4.7455     4.9977     5.3408
   Bi      13.8249     4.9977     8.5475
   O      13.5430     2.9146     0.0000
   O       8.7929     2.9146     3.2067
   O       4.0431     2.9146     6.4135
   Bi       2.5296     5.3196     2.0584
   Bi      11.6090     5.3196     5.2651
   Bi       6.8592     5.3196     8.4718
   O       1.2720     7.4026     2.3087
   O      10.3517     7.4026     5.5154
   O       5.6018     7.4026     8.7222
   Bi      12.8371     3.2698     1.9629
   Bi       8.0872     3.2698     5.1696
   Bi       3.3373     3.2698     8.3760
   O      10.6917     3.7658     0.8980
   O       5.9417     3.7658     4.1044
   O       1.1918     3.7658     7.3112
   Bi      13.0173     7.0475     2.2296
   Bi       8.2673     7.0475     5.4363
   Bi       3.5174     7.0475     8.6430
   O       4.1233     6.5515     1.4110
   O      13.2029     6.5515     4.6177
   O       8.4530     6.5515     7.8241
   Bi       9.5744     1.1287     1.9704
   Bi       4.8244     1.1287     5.1771
   Bi       0.0745     1.1287     8.3838
   O      10.2768     6.7836     0.8980
   O       5.5268     6.7836     4.1044
   O       0.7769     6.7836     7.3112
   Bi       2.7107     1.4506     2.0461
   Bi      11.7903     1.4506     5.2528
   Bi       7.0405     1.4506     8.4595
   O       3.9682     3.5336     1.7957
   O      13.0477     3.5336     5.0025
   O       8.2978     3.5336     8.2092
   O       8.9275     1.2896     0.1282
   O       4.1775     1.2896     3.3350
   O      13.2571     1.2896     6.5417
   O      12.5172     5.1587     2.3728
   O       7.7673     5.1587     5.5795
   O       3.0175     5.1587     8.7863
   O       1.0627     5.1587     0.7695
   O      10.1423     5.1587     3.9762
   O       5.3924     5.1587     7.1829
   O       1.1918     3.7658     7.3112
   Bi      13.0173     7.0475     2.2296
   Bi       8.2673     7.0475     5.4363
   Bi       3.5174     7.0475     8.6430
   O       4.1233     6.5515     1.4110
   O      13.2029     6.5515     4.6177
   O       8.4530     6.5515     7.8241
   Bi       9.5744     1.1287     1.9704
   Bi       4.8244     1.1287     5.1771
   Bi       0.0745     1.1287     8.3838
   O      10.2768     6.7836     0.8980
   O       5.5268     6.7836     4.1044
   O       0.7769     6.7836     7.3112
   Bi       2.7107     1.4506     2.0461
   Bi      11.7903     1.4506     5.2528
   Bi       7.0405     1.4506     8.4595
   O       3.9682     3.5336     1.7957
   O      13.0477     3.5336     5.0025
   O       8.2978     3.5336     8.2092
   O       8.9275     1.2896     0.1282
   O       4.1775     1.2896     3.3350
   O      13.2571     1.2896     6.5417
   O      12.5172     5.1587     2.3728
   O       7.7673     5.1587     5.5795
   O       3.0175     5.1587     8.7863
   O       1.0627     5.1587     0.7695
   O      10.1423     5.1587     3.9762
   O       5.3924     5.1587     7.1829
   O       6.5524     1.2896     1.7316
   O       1.8025     1.2896     4.9383
   O      10.8822     1.2896     8.1451
   Bi       6.2327    14.8768     2.1416
   Bi       1.4827    14.8768     5.3483
   Bi      10.5623    14.8768     8.5550
   O      13.1281    15.3728     0.0000
   O       8.3780    15.3728     3.2067
   O       3.6282    15.3728     6.4135
   Bi       6.0525    10.9165     1.8749
   Bi       1.3026    10.9165     5.0816
   Bi      10.3822    10.9165     8.2883
   O       1.1170    10.4205     2.6938
   O      10.1965    10.4205     5.9002
   O       5.4466    10.4205     9.1069
   Bi       9.4953    12.7357     2.1341
   Bi       4.7455    12.7357     5.3408
   Bi      13.8249    12.7357     8.5475
   O      13.5430    10.6526     0.0000
   O       8.7929    10.6526     3.2067
   O       4.0431    10.6526     6.4135
   Bi       2.5296    13.0576     2.0584
   Bi      11.6090    13.0576     5.2651
   Bi       6.8592    13.0576     8.4718
   O       1.2720    15.1406     2.3087
   O      10.3517    15.1406     5.5154
   O       5.6018    15.1406     8.7222
   Bi      12.8371    11.0078     1.9629
   Bi       8.0872    11.0078     5.1696
   Bi       3.3373    11.0078     8.3760
   O      10.6917    11.5038     0.8980
   O       5.9417    11.5038     4.1044
   O       1.1918    11.5038     7.3112
   Bi      13.0173    14.7855     2.2296
   Bi       8.2673    14.7855     5.4363
   Bi       3.5174    14.7855     8.6430
   O       4.1233    14.2895     1.4110
   O      13.2029    14.2895     4.6177
   O       8.4530    14.2895     7.8241
   Bi       9.5744     8.8667     1.9704
   Bi       4.8244     8.8667     5.1771
   Bi       0.0745     8.8667     8.3838
    O       10.2768    14.5216     0.8980
    O        5.5268    14.5216     4.1044
    O        0.7769    14.5216     7.3112
    Bi        2.7107     9.1886     2.0461
    Bi       11.7903     9.1886     5.2528
    Bi        7.0405     9.1886     8.4595
    O        3.9682    11.2716     1.7957
    O       13.0477    11.2716     5.0025
    O        8.2978    11.2716     8.2092
    O        8.9275     9.0276     0.1282
    O        4.1775     9.0276     3.3350
    O       13.2571     9.0276     6.5417
    O       12.5172    12.8967     2.3728
    O        7.7673    12.8967     5.5795
    O        3.0175    12.8967     8.7863
    O        1.0627    12.8967     0.7695
    O       10.1423    12.8967     3.9762
    O        5.3924    12.8967     7.1829
    O        6.5524     9.0276     1.7316
    O        1.8025     9.0276     4.9383
    O       10.8822     9.0276     8.1451
K_POINTS automatic
1 1 1   0 0 0


-- 
With Best Regards

Dr. G. Krishna Chaitanya
Assistant Professor
School of Chemical Sciences
SRTM University
Nanded-431 606
India.
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