[CP2K-user] [CP2K:21430] Re: SCF Convergence Issues Using SCAN Functional for Dimer Interaction Energy (with BSSE Correction)

[Jürg Hutter]

Hi

you might also want to try r2SCAN. This version is numerically more stable, leading to
better SCF convergence.

regards
JH

________________________________________
From: cp2k at googlegroups.com <cp2k at googlegroups.com> on behalf of Frederick Stein <f.stein at hzdr.de>
Sent: Monday, May 5, 2025 10:09 AM
To: cp2k
Subject: [CP2K:21430] Re: SCF Convergence Issues Using SCAN Functional for Dimer Interaction Energy (with BSSE Correction)

Dear Sam,
Your EPS_DEFAULT is definitely too high, reduce to at least 1.0E-10, better 1.0E-12 or even lower. Keep EPS_PGF_ORB with its default (comment the line out or remove it). In addition, you may also try to increase the CUTOFF.
Best,
Frederick

劉易 schrieb am Montag, 5. Mai 2025 um 07:43:12 UTC+2:

Dear CP2K community,

I am currently using CP2K to compute the interaction energy of a chloroform dimer with BSSE correction, following the counterpoise method. However, I am encountering serious SCF convergence issues when using the SCAN meta-GGA functional.

Has anyone experienced similar issues with SCAN functional in dimer calculations? Is there any recommended strategy for improving SCF convergence in these cases? Any advice on practical workarounds would be greatly appreciated.

Thank you in advance for your help.

Here’s my input file:

&GLOBAL
  PROJECT D_dimer_DISTANCE
  RUN_TYPE BSSE
&END GLOBAL

&FORCE_EVAL
  METHOD Quickstep
  &DFT
    BASIS_SET_FILE_NAME  BASIS_MOLOPT
    POTENTIAL_FILE_NAME  POTENTIAL
    CHARGE 0
    MULTIPLICITY 1

    &MGRID
      CUTOFF 700
    &END MGRID

    &QS
      METHOD GPW
      EPS_DEFAULT  1.0E-8
      EPS_PGF_ORB  1.0E-8
    &END QS

    &SCF
      SCF_GUESS ATOMIC
      EPS_SCF 1.0E-7
      MAX_SCF 3000
      &OT
        MINIMIZER       DIIS
        SAFE_DIIS       T
        PRECONDITIONER  FULL_SINGLE_INVERSE
        ENERGY_GAP      0.002
        STEPSIZE        0.05
      &END
      &OUTER_SCF
        EPS_SCF 1.0E-7
        MAX_SCF 500
      &END
    &END SCF

    &POISSON
      PERIODIC NONE
      PSOLVER  IMPLICIT
    &END POISSON

    &XC
      &XC_FUNCTIONAL
        &MGGA_X_SCAN
        &END MGGA_X_SCAN
        &MGGA_C_SCAN
        &END MGGA_C_SCAN
      &END XC_FUNCTIONAL
    &END XC
  &END DFT

  &SUBSYS
    &CELL
      ABC 16.0 10.0 10.0
      PERIODIC NONE           ! Non periodic calculation.
    &END CELL

    &COORD
C    0.0000000    0.0000000    0.0000000
H    1.0817310    0.0000000    0.0000000
Cl  -0.5404300    1.6724230    0.0000000
Cl  -0.5404300   -0.8362120   -1.4483610
Cl  -0.5404300   -0.8362120    1.4483610
C    3.0000000    0.0000000    0.0000000
H    4.0818090    0.0000000    0.0000000
Cl   2.4467380    1.6699320    0.0000000
Cl   2.4467380   -0.8349660   -1.4462040
Cl   2.4467380   -0.8349660    1.4462040
    &END COORD


    &KIND C_ghost
      ELEMENT C
      GHOST T
      BASIS_SET TZVP-MOLOPT-GTH-q4
      POTENTIAL GTH-SCAN-q4
    &END KIND

    &KIND H_ghost
      ELEMENT H
      GHOST T
      BASIS_SET TZVP-MOLOPT-GTH-q1
      POTENTIAL GTH-SCAN-q1
    &END KIND

    &KIND Cl_ghost
      ELEMENT Cl
      GHOST T
      BASIS_SET TZVP-MOLOPT-GTH-q7
      POTENTIAL GTH-SCAN-q7
    &END KIND

    &KIND C
      ELEMENT C
      BASIS_SET TZVP-MOLOPT-GTH-q4
      POTENTIAL GTH-SCAN-q4
    &END KIND

    &KIND H
      ELEMENT H
      BASIS_SET TZVP-MOLOPT-GTH-q1
      POTENTIAL GTH-SCAN-q1
    &END KIND

    &KIND Cl
      ELEMENT Cl
      BASIS_SET TZVP-MOLOPT-GTH-q7
      POTENTIAL GTH-SCAN-q7
    &END KIND
  &END SUBSYS

  &BSSE
    &FRAGMENT
      LIST 1..5  !  monomer A
    &END FRAGMENT

    &FRAGMENT
      LIST 6..10  !  monomer B
    &END FRAGMENT

    &CONFIGURATION
      GLB_CONF 1 1    ! First & Second FRAGMENT are being used.
      SUB_CONF 1 1    ! E_AB, dimer energy.
      CHARGE 0
      MULTIPLICITY 1
    &END CONFIGURATION

    &CONFIGURATION
      GLB_CONF 1 0    ! Only First FRAGMENT is being used.
      SUB_CONF 1 0    ! E_A, B as ghost, monomer A energy.
      CHARGE 0
      MULTIPLICITY 1
    &END CONFIGURATION

    &CONFIGURATION
      GLB_CONF 0 1    ! Only Second FRAGMENT is being used.
      SUB_CONF 0 1    ! E_B, A as ghost, monomer B energy.
      CHARGE 0
      MULTIPLICITY 1
    &END CONFIGURATION

    &CONFIGURATION
      GLB_CONF 1 1    ! First & Second FRAGMENT are being used.
      SUB_CONF 1 0    ! E_AB(A), B as ghost, monomer A + ghost B
      CHARGE 0
      MULTIPLICITY 1
    &END CONFIGURATION

    &CONFIGURATION
      GLB_CONF 1 1    ! First & Second FRAGMENT are being used.
      SUB_CONF 0 1    ! E_AB(B), A as ghost, monomer B + ghost A
      CHARGE 0
      MULTIPLICITY 1
    &END CONFIGURATION

    &FRAGMENT_ENERGIES
    &END FRAGMENT_ENERGIES

    ! E_BSSE = E_AB - (E_A + E_B) + (E_AB(A) + E_AB(B))

    #&PRINT

    #&END PRINT
  &END BSSE
&END FORCE_EVAL



Best regards,

Sam

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