[CP2K:130] GAPW and GTH

[Juerg Hutter]

Hi Harald

there is an unsolved problem with GAPW: depending on the
basis sets involved, results are very dependent on the
EPS_FIT variable. In you case you can set EPS_FIT to
10^-2 to get reasonable results. Also MD looks much better.

The problem is related to the split of the primitive functions
into hard and soft sets. Changing EPS_FIT moves primitives
from one set to the other. In prinicple this should affect
the total energy only slightly as we trade one source of
errors with another.
I will pu this problem very high on my "to be investigated"
list.

best regards

Juerg

----------------------------------------------------------
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 Mon, 18 Jun 2007, Harald Forbert wrote:

>
> Teo asked me to also post this here:
>
> When calculating HCl with GTH pseudos, I get weird energies with
> GAPW (positive total energy:  +11.6) whereas with GPW
> it is reasonably bound at -15.5. Now if I turn on FULL_GAPW
> it again gives sort of the same energy as GPW, but in both GAPW
> cases the conserved quantity is not conserved - even in a few (5)
> steps MD I get a change of 1e-3 whereas the corresponding
> GPW calculation the conserved quantity only changes by 1.0e-7.
> I did not do a longer MD with FULL_GAPW, but a similar
> calculation with "normal" GAPW also blew up, so it's not just
> a miscalculated conserved quantity.
> Both GPW+GTH and GAPW with all electrons seem to work fine.
> I used the GTH_BASIS_SETS and GTH_POTENTIALS from
> the cvs tree and I pasted the input file below.
>
> Am I doing something wrong, or is GAPW not fully working?
> The same sort of setup works perfectly fine for a single water
> molecule.....
>
> &GLOBAL
>  PROGRAM_NAME  CP2K
>  PROJECT  gapw
>  RUN_TYPE MD
>  PRINT_LEVEL LOW
> &END GLOBAL
> &MOTION
>  &MD
>    ENSEMBLE NVE
>    STEPS 5
>    TIMESTEP 0.2
>    TEMPERATURE 50.0
>  &END MD
> &END MOTION
> &FORCE_EVAL
>  METHOD QS
>  &DFT
>    BASIS_SET_FILE_NAME GTH_BASIS_SETS
>    POTENTIAL_FILE_NAME GTH_POTENTIALS
>    &QS
>       EPS_DEFAULT     1.0E-14
>       EXTRAPOLATION  PS
>       EXTRAPOLATION_ORDER  3
>       METHOD  GAPW
> #       FULL_GAPW T
>       MAP_CONSISTENT T
>    &END QS
>    &SCF
>       MAX_SCF     100
>       EPS_SCF     1.0E-7
>       CHOLESKY F
>       SCF_GUESS  ATOMIC
>    &END SCF
>    &MGRID
>      CUTOFF 400
>    &END MGRID
>    &XC
>      &XC_FUNCTIONAL BLYP
>      &END XC_FUNCTIONAL
>    &END XC
>  &END DFT
>  &SUBSYS
>    &CELL
>      ABC 8.0 8.0 8.0
>      UNIT ANGSTROM
>    &END CELL
>    &COORD
>       Cl         0.9564675869       -0.4777215658        0.1818080168
>        H        -0.1657168075        0.1752674377       -0.0159958272
>    &END COORD
>    &VELOCITY
>        1.57689068E-05  2.13541290E-05  1.89890498E-06
>      -2.92031628E-04  6.55172505E-05  1.82242571E-04
>    &END VELOCITY
>    &KIND Cl
>       BASIS_SET TZV2P-GTH
>       MASS     3.4968852720999998E+01
>       POTENTIAL GTH-BLYP-q7
>    &END KIND
>    &KIND H
>       BASIS_SET TZV2P-GTH
>       MASS     1.0079469999999999E+00
>       POTENTIAL GTH-BLYP-q1
>    &END KIND
>  &END SUBSYS
> &END FORCE_EVAL
>
>
> >
>