[Pw_forum] crystal coordinates and ibrav=12

[Andrea Vittadini]

Hi all,

anybody tried to run PWSCF calculations on a Monoclinic cell (ibrav=12)
with "crystal" coordinates?

I used two coordinates sets, both with the following cell parameters:
celldm(1)=   7.154503  celldm(2)=   2.759416  celldm(3)=   1.000000
celldm(4)=   0.362396

As far as I can see, sets 1&2 should be (approximately) equivalent, yet
set #1 gives strange results.
I tried both espresso 2.1.4 and 3.0: no change.

The following are the coordinates sets:

=============  set #1  ===============
ATOMIC_POSITIONS {crystal}
   O    0.95595    0.95595    0.50000
   O    0.54405    0.04405    0.00000
   O    0.20596    0.20595    0.00000
   O    0.79405    0.29405    0.50000
   O    0.95596    0.45596    0.00000
   O    0.54405    0.54405    0.50000
   O    0.20596    0.70596    0.50000
   O    0.79405    0.79405    0.00000
  Ti    0.00000    0.00000    0.00000
  Ti    0.75000    0.25000    0.00000
  Ti    0.00000    0.50000    0.50000
  Ti    0.75000    0.75000    0.50000
=============  set #2  ===============
ATOMIC_POSITIONS
O     0.0000000  -0.1132771   0.5000000
O     0.5000000   0.1132771   0.0000000
O     0.0000000   0.5296840   0.0000000
O     0.5000000   0.7562383   0.5000000
O     0.5000000   1.1726452   0.0000000
O     0.0000000   1.3991994   0.5000000
O     0.5000000   1.8156063   0.5000000
O     0.0000000   2.0421606   0.0000000
Ti    0.0000000   0.0000000   0.0000000
Ti    0.5000000   0.6429612   0.0000000
Ti    0.5000000   1.2859223   0.5000000
Ti    0.0000000   1.9288834   0.5000000
=======================================


-- 
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 Andrea Vittadini
 Istituto di Scienze e Tecnologie Molecolari del CNR 
 CNR Institute of Molecular Science and Technologies 

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 Dip. Scienze Chimiche                 EMAIL : andrea.vittadini at unipd.it
 via Marzolo 1                         PHONE : +39 049 827 5235
 I-35131 Padova, Italy                 FAX   : +39 049 827 5161
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