[CP2K:423] Re: grid settings

Nicolas Bock nicol... at gmail.com
Mon Dec 3 18:20:28 CET 2007


Thanks for all the suggestions. I have another question however: When
I increase the cell size to

    &CELL
      ABC 8.0 8.0 8.0
      PERIODIC NONE
      UNITS ANGSTROM
    &END CELL

cp2k dies with a segmentation fault. Is that a known problem? Is there
a problem with my compilation?

Thanks, nick


On Nov 30, 2007 5:15 AM, Juerg Hutter <hut... at pci.uzh.ch> wrote:
>
> Hi
>
> this is a GAPW calculation. The charge you refer to is only
> the charge on the equidistant PW grid. The total charge
> on all grids is for your input
>
> Total Rho_soft + Rho1_hard - Rho1_soft (r-space):               -1.9999999929
>
> As Teo already pointed out you can improve the energy by
> using another Poisson solver and/or increasing the box size.
> If you also use a higher cutoff for the grid, e.g.
>
>      &MGRID
>          CUTOFF  360
>      &END
>
> You get to an energy of
>
> -1.15977265992678
>
> that is only 1.4*10^-6 Hartree different from GAMESS.
>
> GAPW uses a one center expansion of the density based on
> the basis set used. For small basis sets (like 6-31G*)
> this leads to rather small expansions and some errors
> are introduced. It's expected that this error is reduced
> for larger (with more primitives) basis sets.
>
> regards
>
> Juerg Hutter
>
> ----------------------------------------------------------
> Juerg Hutter                   Phone : ++41 44 635 4491
> Physical Chemistry Institute   FAX   : ++41 44 635 6838
> University of Zurich           E-mail: hut... at pci.uzh.ch
> Winterthurerstrasse 190
> CH-8057 Zurich, Switzerland
> ----------------------------------------------------------
>
>
>
> On Thu, 29 Nov 2007, nicol... at gmail.com wrote:
>
> >
> > I forgot to mention the results I get:
> >
> > Total energy:
> > gamess = -1.1597712381
> > cp2k = -1.1598787278
> >
> > total electron number:
> > gamess = 1.9999986580
> > cp2k = -1.9869016182
> >
> > On Nov 29, 8:40 pm, "nicol... at gmail.com" <nicol... at gmail.com>
> > wrote:
> >> Hello list,
> >>
> >> I am trying to get familiar with cp2k and wrote a very simple H_2 DFT
> >> input file. I compare the result with gamess. I somehow can't seem to
> >> get both into very good agreement. I suspect that this is a grid issue
> >> within cp2k since the total electron charge is not very close to 2.
> >> Could someone on this list give me a hint as to what I need to change
> >> in the input file to get better answers?
> >>
> >> Thanks already,
> >>
> >> nick
> >>
> >> gamess input file:
> >>
> >>  $CONTRL
> >>    EXETYP=RUN
> >>    DFTTYP=BLYP
> >>    RUNTYP=GRADIENT
> >>    COORD=UNIQUE
> >>    UNITS=ANGS
> >>  $END
> >>  $SYSTEM TIMLIM=1 MEMDDI=1 PARALL=.TRUE. $END
> >>  $BASIS GBASIS=N31 NGAUSS=6 $END
> >>  $GUESS GUESS=HUCKEL $END
> >>  $DATA
> >> Hydrogen molecule
> >> Cnv      1
> >>
> >> HYDROGEN   1.0   0.0   0.0   0.85
> >> HYDROGEN   1.0   0.0   0.0   0.0
> >>  $END
> >>
> >> cp2k input file
> >>
> >> &FORCE_EVAL
> >>   METHOD Quickstep
> >>   &DFT
> >>     &SCF
> >>       SCF_GUESS ATOMIC
> >>     &END SCF
> >>     &XC
> >>       &XC_FUNCTIONAL BLYP
> >>       &END XC_FUNCTIONAL
> >>     &END XC
> >>     &QS
> >>       METHOD GAPW
> >>     &END QS
> >>     &POISSON
> >>       POISSON_SOLVER ANALYTIC
> >>       PERIODIC NONE
> >>     &END POISSON
> >>   &END DFT
> >>   &SUBSYS
> >>     &CELL
> >>       ABC 7.0 7.0 7.0
> >>       PERIODIC NONE
> >>       UNITS ANGSTROM
> >>     &END CELL
> >>     &COORD
> >>       H 0.0 0.0 0.85
> >>       H 0.0 0.0 0.0
> >>     &END COORD
> >>     &KIND H
> >>       BASIS_SET 6-31G*
> >>       POTENTIAL ALL
> >>     &END KIND
> >>   &END SUBSYS
> >> &END FORCE_EVAL
> >> &GLOBAL
> >>   PROJECT H2-cp2k
> >>   RUN_TYPE ENERGY_FORCE
> >> &END GLOBAL
> > >
> >
>
> >
>



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