Dipole moments in CP2K

[Ant]

I would like to repost a question I first asked a few days ago.  There were no responses and the question was likely unclear.  I hope to have improved it.

I would like to use CP2K (Quickstep) to reproduce a predecessor's calculations of the static relative permittivity.  He used a different code.  So far our results are the same at lower pressure, but differ as pressure increases.  I am trying to figure out why this might be happening.

In CP2K, the calculation involves outputting the dipole moment.  Maybe there is someone out there who knows whether CP2K may have advantages or disadvantages as far as calculating the dipole moment compared to other codes?  

I have used the same physical conditions/ensemble, time step, functional, kinetic energy cutoff, and boundary conditions (periodic) as my predecessor did.  He used twice the number of molecules that I'm using and he also used "heavy" water.  There's no other information available.  I'm a bit of a newbie, so if anyone knows of any other possible source of discrepancy, I would be grateful for any tips.  Thank you. 

[Marcella Iannuzzi]

Dear Ant, 

There are no particular issues in calculating the dipole moment with cp2k, provided that the right methods and settings are used. 

It is not possible to give any advise with respect to the comparison to other codes without more information. 

Regards

Marcella

[Ant]

Dear Marcella:

Thank you very much for your reply.  

I can provide the following input file that I have been using as a template.  As I said, when I use a lower pressure, my results coincide with the ones calculated using the other code that my colleague used.  When I use a higher pressure, the results are very different.  I'm not sure if there is enough information to identify potential problems; however, maybe a more experienced user might see a setting I have used that is not optimal.  Thank you.

&GLOBAL

  PROJECT XXX

  RUN_TYPE MD

&END GLOBAL

&FORCE_EVAL

  STRESS_TENSOR  ANALYTICAL

  METHOD  Quickstep

  &DFT

    &PRINT

      &MOMENTS

      FILENAME = moments

      ADD_LAST NUMERIC

      PERIODIC TRUE

      &EACH

        MD 1

      &END

      &END MOMENTS

    &END PRINT

    BASIS_SET_FILE_NAME BASIS_MOLOPT

    POTENTIAL_FILE_NAME POTENTIAL_SET

    CHARGE 0

    MULTIPLICITY 1

    &MGRID

       CUTOFF [Ry] XXX

       REL_CUTOFF [Ry] XXX

    &END

    &QS

       EPS_DEFAULT 1.0E-10

       EXTRAPOLATION ASPC

       EXTRAPOLATION_ORDER 4

    &END QS

    &POISSON

       PERIODIC XYZ

    &END

    &SCF

      SCF_GUESS ATOMIC

      MAX_SCF 30

      EPS_SCF 1.0E-6

      &OT

        PRECONDITIONER FULL_SINGLE_INVERSE

        MINIMIZER DIIS

      &END OT

      &OUTER_SCF

        MAX_SCF 10

        EPS_SCF 1.0E-6

      &END

      &PRINT

        &RESTART OFF

        &END

      &END

    &END SCF

    &XC

      &XC_FUNCTIONAL

         &PBE

         &END

      &END XC_FUNCTIONAL

      &XC_GRID

            XC_DERIV  SPLINE2_SMOOTH

            XC_SMOOTH_RHO NN50

      &END XC_GRID

      &VDW_POTENTIAL

         POTENTIAL_TYPE PAIR_POTENTIAL

         &PAIR_POTENTIAL

            PARAMETER_FILE_NAME dftd3.dat

            TYPE DFTD3

            REFERENCE_FUNCTIONAL PBE

            R_CUTOFF [angstrom] 16

         &END

      &END VDW_POTENTIAL

    &END XC

  &END DFT

  &SUBSYS

    &CELL

      ABC XXX XXX XXX

    &END CELL

    &COORD

      XXX

    &END COORD

    &TOPOLOGY

      CONNECTIVITY GENERATE

      &GENERATE

        BONDLENGTH_MAX 7

      &END

    &END

    &KIND H

      BASIS_SET DZVP-MOLOPT-SR-GTH

      POTENTIAL GTH-NLCC-PBE-q1

    &END KIND

    &KIND O

      BASIS_SET DZVP-MOLOPT-SR-GTH

      POTENTIAL GTH-NLCC-PBE-q6

    &END KIND

  &END SUBSYS

&END FORCE_EVAL

&MOTION

 &MD

   ENSEMBLE  NPT_I

   TEMPERATURE  [K] XXX

   TIMESTEP [fs] 0.5

   STEPS XXX

   &THERMOSTAT

     &NOSE

       LENGTH 3

       YOSHIDA 3

       TIMECON 1000

       MTS 2

     &END NOSE

   &END THERMOSTAT

   &BAROSTAT

     PRESSURE XXX

   &END BAROSTAT

  &END MD

  &PRINT

    &CELL

    &END

    &RESTART_HISTORY OFF

    &END

  &END PRINT

&END MOTION