[CP2K:7394] Optimisation of solid state compound

Ari Paavo Seitsonen ari.p.s... at gmail.com
Tue Feb 2 20:45:38 CET 2016


Dear Matthew,

  If no one else replies... I have serious doubts about your input: The
cut-off energy has a historical, (very) low value; you only take one unit
cell, and since there are no k points (in your input), you rely on the
sampling of the Gamma-point only; what is the electronic structure of this
solid, is it possibly metallic, magnetic, strongly-correlated? Maybe the
problem is related to one of those issues...?

    Good Luck and Greetings from Montrouge,

       apsi

2016-02-02 14:35 GMT+01:00 <mj.be... at hotmail.co.uk>:

> Dear all,
>
> I am currently studying solid state compounds using DFT methods with PBE
> incp2k v2.6. In particular, I am studying the compound SrO. I, however, am
> having trouble at the first hurdle as I am unable to optimise the structure
> without massive distortions taking place in the structure. I have also done
> this for a more simple compound such as SrO but still maintain the same
> problem. The resulting structure after the calculation has finished heavily
> distorted and is not in fact optimised. The coordinates used in the input
> file are those after those of when the atoms repeated by symmetry have been
> deleted.
>
> Here is my input:
>
> &FORCE_EVAL
>   METHOD Quickstep
>   &DFT
>   BASIS_SET_FILE_NAME  ./BASIS_MOLOPT
>   POTENTIAL_FILE_NAME ./GTH_POTENTIALS
>     &MGRID
>       CUTOFF 280
>     &END MGRID
>     &QS
>     &END QS
>     &SCF
>       EPS_SCF 1.0E-7
>       MAX_SCF 500
>       SCF_GUESS RESTART
>       &OT
>        PRECONDITIONER FULL_ALL
>        MINIMIZER DIIS
>       &END OT
>     &END SCF
>     &POISSON
>     POISSON_SOLVER PERIODIC
>     PERIODIC       XYZ
>     &END POISSON
>     &XC
>       &XC_FUNCTIONAL PBE
>       &END XC_FUNCTIONAL
>     &END XC
>     &PRINT
>      &E_DENSITY_CUBE
>      &END
>     &END
>   &END DFT
>   &SUBSYS
>     &CELL
> ABC  5.161500   5.161500   5.161500
>     &END CELL
>     &COORD
> Sr    2.580750    2.580750    2.580750
> Sr    2.580750    5.161500    0.000000
> Sr    0.000000    2.580750    0.000000
> Sr    0.000000    0.000000    2.580750
>  O    0.000000    0.000000    0.000000
>  O    0.000000    2.580750    2.580750
>  O    2.580750    0.000000    2.580750
>  O    2.580750    2.580750    0.000000
>     &END COORD
>     &KIND Sr
>       BASIS_SET DZVP-MOLOPT-SR-GTH
>       POTENTIAL GTH-PBE-q10
>     &END KIND
>     &KIND O
>       BASIS_SET DZVP-MOLOPT-SR-GTH
>       POTENTIAL GTH-PBE-q6
>     &END KIND
> &TOPOLOGY
> &GENERATE
> BONDLENGTH_MAX 8.
> &END
> &END
>   &END SUBSYS
> &END FORCE_EVAL
> &GLOBAL
>   PROJECT SrO_GEOPT
>   RUN_TYPE GEO_OPT
>   PRINT_LEVEL MEDIUM
>   PREFERRED_FFT_LIBRARY FFTSG
> &END GLOBAL
>
> &MOTION
>   &GEO_OPT
>     MAX_ITER 300
>     MAX_FORCE 1.E-5
>     OPTIMIZER BFGS
>   &END GEO_OPT
> &END MOTION
>
>
>
>  Here is the coordinates for the resulting geometry of SrO:
>
>
>      &CELL
>        A     5.1615000000000002E+00    0.0000000000000000E+00
> 0.0000000000000000E+00
>        B     0.0000000000000000E+00    5.1615000000000002E+00
> 0.0000000000000000E+00
>        C     0.0000000000000000E+00    0.0000000000000000E+00
> 5.1615000000000002E+00
>        MULTIPLE_UNIT_CELL  1 1 1
>      &END CELL
>      &COORD
> Sr    1.9890028994522615E+00    2.2193294449078076E+00
> 2.7910266626701881E+00
> Sr    1.9292986629548623E+00    4.8135192380570206E+00
> 2.1296902553214103E-01
> Sr   -5.9176277362609420E-01    2.7509938085013901E+00
>  -3.0581129089048587E-01
> Sr   -6.5144865196079582E-01    1.5680073585860360E-01
> 2.2722491342258304E+00
> O    4.7898927316432355E-01    8.6395713176665057E-01
>  -1.0487832154631918E+00
> O    4.7694627804364587E-01    3.4395703896268177E+00
> 1.6198967879945019E+00
> O    3.0597429820934190E+00   -1.0551228958752437E+00
> 3.5339829819921467E+00
> O    3.0576968263194555E+00    1.5307475361163412E+00
> 8.6527187533043926E-01
>     &END COORD
>
>
> I am really unsure what the problem is and would appreciate any help that
> people can give me.
>
> Many Thanks
>
> Matthew Bennett
>
>
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-- 
-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
  Ari Paavo Seitsonen / Ari.P.S... at iki.fi / http://www.iki.fi/~apsi/
    Ecole Normale Supérieure (ENS), Département de Chimie, Paris
    Mobile (F) : +33 789 37 24 25    (CH) : +41 79 71 90 935
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