[Pw_forum] A problem about relax

[Nicholas E. Singh-Miller]

Hi Lihui,

>From a quick glace at the coordinates it seems that you have some atoms 
that should be equivalent by translational symmetry (although 
even then there seem to be other issuses with the coordinates).  A quick 
and easy way to check these things would be with Xcrysden (esp for pwscf)
http://www.xcrysden.org/

-Nick



On Wed, 7 Nov 2007, oulihui666 wrote:

> Dear pwscf users:
>      I am now doing a large job of 'relax' calculation. The unit cell contains 20 atoms and vacuum. The job has been running for seven days. While the total energy is decreasing, the amount it decreases is approximately a constant. We calculated the Pt(111) surface with pwscf, we use a five-layer slab containing 20 Pt atoms,  the atoms in the bottom three layers are fixed, and the others are allowed to relax. The input file and structure can be found in below. However, calculated results indicated, the atoms in the top two layers are not inward or outward relaxation, but upward or downward relaxation,  Could you tell me whether the input file is correct or not? and the final structure is correct or not please?
> Thanks a lot
> Best wishes
> Lihui Ou
>
>
>
> &CONTROL
>
>                 calculation = 'relax' ,
>
>                restart_mode = 'from_scratch' ,
>
>                      outdir = '/home/olh/tmp/' ,
>
>                  pseudo_dir = '/home/olh/pseudo/' ,
>
>                      prefix = 'Pt111_20' ,
>
>                     tstress = .true. ,
>
>                     tprnfor = .true. ,
>
> /
>
> &SYSTEM
>
>                       ibrav = 4,
>
>                           A = 5.549 ,
>
>                           B = 5.549 ,
>
>                           C = 21.062 ,
>
>                       cosAB = -0.5 ,
>
>                       cosAC = 0 ,
>
>                       cosBC = 0 ,
>
>                         nat = 20,
>
>                        ntyp = 1,
>
>                     ecutwfc = 70 ,
>
>                     ecutrho = 0 ,
>
>                 occupations = 'smearing' ,
>
>                     degauss = 0.02 ,
>
>                    smearing = 'gaussian' ,
>
> /
>
> &ELECTRONS
>
>                    conv_thr = 1.0D-8 ,
>
>                 mixing_beta = 0.7D0 ,
>
>             diagonalization = 'david' ,
>
> /
>
> &IONS
>
> /
>
> ATOMIC_SPECIES
>
>   Pt  195.09000  Pt.pz-rrkjus.linux.UPF
>
> ATOMIC_POSITIONS angstrom
>
>   Pt     -0.000000000    0.000000000   -9.062000000    0  0  0
>
>   Pt     -0.000000000    2.775000000   -9.062000000    0  0  0
>
>   Pt      2.403000000   -1.387000000   -9.062000000    0  0  0
>
>   Pt      2.403000000    1.387000000   -9.062000000    0  0  0
>
>   Pt     -0.000000000   -0.000000000   -2.265000000    1  1  1
>
>   Pt     -0.000000000    2.775000000   -2.265000000    1  1  1
>
>   Pt      2.403000000   -1.387000000   -2.265000000    1  1  1
>
>   Pt      2.403000000    1.387000000   -2.265000000    1  1  1
>
>   Pt      1.602000000    0.000000000   -4.531000000    0  0  0
>
>   Pt      1.602000000    2.775000000   -4.531000000    0  0  0
>
>   Pt      4.005000000   -1.387000000   -4.531000000    0  0  0
>
>   Pt      4.005000000    1.387000000   -4.531000000    0  0  0
>
>   Pt      0.801000000    1.387000000   -6.796000000    0  0  0
>
>   Pt      0.801000000    4.162000000   -6.796000000    0  0  0
>
>   Pt      3.204000000    0.000000000   -6.796000000    0  0  0
>
>   Pt      3.204000000    2.775000000   -6.796000000    0  0  0
>
>   Pt      0.801000000    1.387000000   -0.000000000    1  1  1
>
>   Pt      0.801000000    4.162000000   -0.000000000    1  1  1
>
>   Pt      3.204000000   -0.000000000   -0.000000000    1  1  1
>
>   Pt      3.204000000    2.775000000   -0.000000000    1  1  1
>
> K_POINTS automatic
>
>  3 3 1   1 1 1
>
>
>
> --
>
> ======================================
> Lihui Ou
> PH.D Candidate in Electrochemistry
> College of Chemistry and Molecular Science
> Wuhan University,430072,Hubei Province,China
> E-mail:oulihui666 at 126.com
> ======================================

*****************************************
Nicholas E. Singh-Miller
Ph.D. Candidate
Prof. Marzari Group (quasiamore.mit.edu)
Materials Science and Engineering
Massachusetts Institute of Technology
13-4066
(617)324-0372
*****************************************