[CP2K-user] Calculating dipole moments for static dielectric constant calculation. Please help me decide whether and how to use Ewald summation.

[Stns]

I would like to repeat calculations of the static dielectric constant that 
someone did years ago with a different code, for use in other 
calculations.  My basic setup is below.

I'm not an expert and it's a challenge.  One previous problem was that I 
did not realize I was not calculating "traditional" dipole moments that are 
compatible with the fluctuation formula used in exercises like the one at 
the link in red below.  I now include "PERIODIC FALSE" (please see my setup 
at the bottom of this message) and the problem seems to have been fixed, 
but I mention it here in case it is not.
https://www.cp2k.org/exercises:2018_uzh_acpc2:mol_sol

The issue now is that I have realized I should be using Ewald summation in 
my periodic boundary conditions.  I thought I was (that it was the 
default).  In my setup below that I have been using, I have:

    &POISSON

       PERIODIC XYZ 

    &END

However, I came across an example input file in a CP2K exercise online and 
saw that he included explicit language related to Ewald summation, so it 
appears I have not been using it so far.  The example uses:

    &POISSON

      &EWALD

        EWALD_TYPE ewald

        ALPHA .45

        GMAX  19

      &END EWALD

    &END POISSON

*Could someone please point me in the right direction?  *Should I replace 
my simple "PERIODIC XYZ" with the example directly above (in red)?  How can 
I figure out reasonable values for ALPHA and GMAX if so?  Any advice would 
be very helpful.  Thank you.


My setup (below).

&GLOBAL

  PROJECT X

  RUN_TYPE MD

&END GLOBAL

&FORCE_EVAL

  STRESS_TENSOR  ANALYTICAL

  METHOD  Quickstep

  &DFT

    &PRINT

      &MOMENTS

      FILENAME = moments

      ADD_LAST NUMERIC

      PERIODIC FALSE

      &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] 600

       REL_CUTOFF [Ry] 60

    &END

    &QS

       METHOD GPW

       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 X X X

    &END CELL

    &COORD

      XXX

    &END COORD

    &TOPOLOGY

    &END

    &KIND X

      BASIS_SET DZVP-MOLOPT-SR-GTH

      POTENTIAL GTH-PBE-q9

    &END KIND

  &END SUBSYS

&END FORCE_EVAL

&MOTION

  &MD

     XXX

  &END MD

  &PRINT

    …

  &END PRINT

&END MOTION
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