[Wien] Volume of BP unit cell.

[tran at theochem.tuwien.ac.at]

The lattice constants are those of the conventional unit cell.
:VOL is the volume of the primitive unit cell.


On Monday 2016-06-27 11:17, Luciano Ortenzi wrote:

>Date: Mon, 27 Jun 2016 11:17:47
>From: Luciano Ortenzi <Luciano.Ortenzi at sapienza.isc.cnr.it>
>Reply-To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
>To: wien at zeus.theochem.tuwien.ac.at
>Subject: [Wien] Volume of BP unit cell.
>
>
> Dear all,
>
> Before calculating the bandstructure of black phosphorus at ambient pressure 
> (space group 64_Cmca)
> I run a scf cicle and check for the unit cell volume (grep :VOL *.scf).
> It turns out that the volume of the unit cell is half of the value I expected.
> Namely
>
> :VOL  : UNIT CELL VOLUME =     501.04679
>
> while the product of the lattice parameters (the system is orthorhombic)
>
> is a*b*c=1002,09359 Bohr^3.
>
> Here is the struct file.
> Best!
>
> Title
> CXY LATTICE,NONEQUIV.ATOMS:  1 64_Cmca
> MODE OF CALC=RELA unit=ang
> 6.264445 19.558673  8.178738 90.000000 90.000000 90.000000
> ATOM  -1: X=0.00000000 Y=0.10240000 Z=0.08000000
>         MULT= 4          ISPLIT= 8
>     -1: X=0.00000000 Y=0.89760000 Z=0.92000000
>     -1: X=0.00000000 Y=0.60240000 Z=0.42000000
>     -1: X=0.00000000 Y=0.39760000 Z=0.58000000
> P          NPT=  781  R0=0.00010000 RMT= 2.08        Z: 15.0
> LOCAL ROT MATRIX:    0.0000000 0.0000000 1.0000000
>                    1.0000000 0.0000000 0.0000000
>                    0.0000000 1.0000000 0.0000000
>  8      NUMBER OF SYMMETRY OPERATIONS
> -1 0 0 0.00000000
> 0-1 0 0.00000000
> 0 0-1 0.00000000
>      1
> -1 0 0 0.00000000
> 0 1 0 0.00000000
> 0 0 1 0.00000000
>      2
> 1 0 0 0.00000000
> 0-1 0 0.00000000
> 0 0-1 0.00000000
>      3
> 1 0 0 0.00000000
> 0 1 0 0.00000000
> 0 0 1 0.00000000
>      4
> -1 0 0 0.00000000
> 0-1 0 0.50000000
> 0 0 1 0.50000000
>      5
> -1 0 0 0.00000000
> 0 1 0 0.50000000
> 0 0-1 0.50000000
>      6
> 1 0 0 0.00000000
> 0-1 0 0.50000000
> 0 0 1 0.50000000
>      7
> 1 0 0 0.00000000
> 0 1 0 0.50000000
> 0 0-1 0.50000000
>      8
>
>
>
> -----------------------------------------------
> Luciano Ortenzi, PhD
> ISC-CNR
> c/o Department of Physics
> University of Rome "La Sapienza"
> P.le A. Moro 5, 00185 Rome (Italy)
> Tel: +39-06-49913489
> e-mail: Luciano.ortenzi at isc.cnr.it
> web page: http://www.isc.cnr.it/staff-members/luciano-ortenzi/
> -----------------------------------------------
>
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