[CP2K:3891] high binding energy

[Sandeep Kumar Reddy]

Hi,
    I used same functional (BLYP + D) and same Poisson solver, but
different PP (T*roullier*-*Martins). I will check with G*oedecker PP.


Regards,

Sandeep
1



On Wed, Jul 4, 2012 at 1:45 PM, <hut... at pci.uzh.ch> wrote:

> Hi
>
> Maybe you should really use exactly the same setup (Basis and Functional
> using GAPW) as
> a starting point and then step for step introduce pseudopotentials and
> other basis sets and e.g. dispersion corrections.
> The comparision with CPMD has been done with the same PP and functionals
> (BLYP+D2),
> and Poisson solver?
> If yes, this would point towards a basis set problem.
>
> 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
> ---------------------------------------------------------------
>
> -----cp... at googlegroups.com wrote: -----
> To: cp... at googlegroups.com
> From: Sandeep Kumar Reddy
> Sent by: cp... at googlegroups.com
> Date: 07/02/2012 03:13PM
> Subject: [CP2K:3886] high binding energy
>
> Dear all,
>              I want to calculate binding energy and compare with
> Gaussian's result and then i would like to proceed to bulk simulations.
>
> My system one ion pair (it's an ionic liquid). I did geometry
> optimizations of cation, anion and ion-pair and calculated the binding
> energy. This value is equal to  -119 kcal/mol. After adding BSSE
> corrections, it is reduced to -116 kcal/mol. For comparison, i carried out
> same calculations at MP2/aug-cc-pVDZ level using Gaussian package and this
> value is equal to -104 kcal/mol (BSSE corrected). A difference of 10
> kcal/mol of such calculation is discouraging.
>
> (I have used same functional, cell parameters, cutoff, potentials for all
> three calculations)
>
>
> I repeated the calculations by changing cutoff (to 480 Ry) and increasing
> box length (20 \AA). But it gives me same binding energy. Additionally, i
> have done same calculations in plane wave basis set using CPMD code. It
> gives 105 kcal/mol, very close to MP2 result.
>
> I am not able to figure out why it happens.  Could anybody comment on my
> input files ?
>
>
> Ion-pair :
>
> &GLOBAL
>   PROJECT dimethyl_ammonium_bromide
>   RUN_TYPE GEO_OPT
>   PRINT_LEVEL MEDIUM
> &END GLOBAL
>
> &FORCE_EVAL
>   METHOD Quickstep
>   &DFT
>     BASIS_SET_FILE_NAME  /panfs/home/Xsreddy/cp2k/tests/QS/BASIS_MOLOPT
>     POTENTIAL_FILE_NAME  /panfs/home/Xsreddy/cp2k/tests/QS/POTENTIAL
>     &MGRID
>       CUTOFF 280
>       NGRIDS 5
>     &END MGRID
>     &QS
>       METHOD       GPW
>       EPS_DEFAULT  1.0E-10
>     &END QS
>     &SCF
>       MAX_SCF   50
>       EPS_SCF   1.0E-6
>       SCF_GUESS ATOMIC
>       &OT ON
>         MINIMIZER       CG
>         PRECONDITIONER  FULL_ALL
>         ENERGY_GAP      0.001
>       &END OT
>       &OUTER_SCF
>         MAX_SCF  100
>         EPS_SCF  1.0E-6
>       &END OUTER_SCF
>     &END SCF
>     &XC
>       &XC_FUNCTIONAL  BLYP
>       &END XC_FUNCTIONAL
>       &vdW_POTENTIAL
>         DISPERSION_FUNCTIONAL PAIR_POTENTIAL
>          &PAIR_POTENTIAL
>           TYPE DFTD2
>           REFERENCE_FUNCTIONAL BLYP
>         &END PAIR_POTENTIAL
>       &END vdW_POTENTIAL
>     &END XC
>      &POISSON
>      POISSON_SOLVER WAVELET
>      PERIODIC NONE
>     &END POISSON
>   &END DFT
>   &SUBSYS
>     &CELL
>       ABC 20.0 20.0 20.0
>       PERIODIC NONE
>     &END CELL
>     &COORD
>     H       1.82622900    0.00011700    1.45609900
>     H       0.41368700   -0.00011700    0.43855600
>     N       1.53927100    0.00002300    0.47861600
>     C       1.97625500   -1.24136700   -0.20041700
>     H       3.06445100   -1.28419200   -0.25417500
>     H       1.58040100   -2.09266400    0.34985900
>     H       1.53907000   -1.23367800   -1.19754500
>     C       1.97589400    1.24149000   -0.20039300
>     H       1.54099200    1.23242900   -1.19850300
>     H       1.57755100    2.09264100    0.34831700
>     H       3.06414500    1.28582600   -0.25177600
>     Br     -1.40269500   -0.00003600   -0.01818000
>     &END COORD
>     &TOPOLOGY
>       &CENTER_COORDINATES
>       &END
>     &END
>     &KIND H
>       BASIS_SET  DZVP-MOLOPT-GTH
>       POTENTIAL  GTH-BLYP-q1
>     &END KIND
>     &KIND C
>       BASIS_SET  DZVP-MOLOPT-GTH
>       POTENTIAL  GTH-BLYP-q4
>      &END KIND
>     &KIND N
>       BASIS_SET  DZVP-MOLOPT-GTH
>       POTENTIAL  GTH-BLYP-q5
>     &END KIND
>     &KIND Br
>       BASIS_SET  DZVP-MOLOPT-SR-GTH
>       POTENTIAL  GTH-BLYP-q7
>     &END KIND
>   &END SUBSYS
> &END FORCE_EVAL
> &MOTION
>   &GEO_OPT
>     MAX_FORCE 0.0001
>     MAX_ITER 500
>     OPTIMIZER BFGS
>   &END GEO_OPT
> &END MOTION
>
>
> Other input files are enclosed.
>
> Thanks.
>
> Regards,
>  Sandeep
>
>
>
>
>
>
>
>
>
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>
> [attachment "ion-pair.in" removed by Jürg Hutter/at/UZH]
> [attachment "cation.in" removed by Jürg Hutter/at/UZH]
> [attachment "anion.in" removed by Jürg Hutter/at/UZH]
>
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