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.<div> </div><div>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.</div><div>https://www.cp2k.org/exercises:2018_uzh_acpc2:mol_sol</div><div> </div><div><div>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:</div><div> </div><div> &POISSON PERIODIC XYZ &END</div><div> </div><div>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:</div><div> </div><div> &POISSON &EWALD EWALD_TYPE ewald ALPHA .45 GMAX 19 &END EWALD &END POISSONCould 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).</div><div> &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</div></div>