! h2o_energy_force.inp - energy AND atomic forces of an isolated water molecule
! Tutorial: CP2K chapter 2, section 9.  Works with CP2K 2023.x - 2026.2.
! Run:   rm -f h2o_ef.out; cp2k.ssmp -i h2o_energy_force.inp -o h2o_ef.out
! Look:  grep -A6 "FORCES|" h2o_ef.out          (CP2K >= 2025.1 screen format)
!        grep -A6 "ATOMIC FORCES" h2o_ef.out    (CP2K <= 2024.x)

&GLOBAL
  PROJECT h2o_ef
  RUN_TYPE ENERGY_FORCE       ! energy + analytic forces on all atoms
  PRINT_LEVEL MEDIUM
&END GLOBAL

&FORCE_EVAL
  METHOD QS
  &PRINT
    &FORCES ON                ! print forces (default unit: hartree/bohr)
    &END FORCES
  &END PRINT
  &DFT
    BASIS_SET_FILE_NAME BASIS_MOLOPT
    POTENTIAL_FILE_NAME GTH_POTENTIALS
    &MGRID
      CUTOFF 400
      REL_CUTOFF 50
    &END MGRID
    &QS
      EPS_DEFAULT 1.0E-12     ! forces need tighter screening than energies
    &END QS
    &POISSON
      PERIODIC NONE
      POISSON_SOLVER MT
    &END POISSON
    &SCF
      EPS_SCF 1.0E-7          ! tighter SCF: forces are more sensitive than energies
      MAX_SCF 30
      &OT ON
        MINIMIZER DIIS
        PRECONDITIONER FULL_SINGLE_INVERSE
      &END OT
      &OUTER_SCF ON
        EPS_SCF 1.0E-7
        MAX_SCF 10
      &END OUTER_SCF
      &PRINT
        &RESTART ON           ! write h2o_ef-RESTART.wfn (on by default, shown for clarity)
        &END RESTART
      &END PRINT
    &END SCF
    &XC
      &XC_FUNCTIONAL PBE
      &END XC_FUNCTIONAL
    &END XC
  &END DFT
  &SUBSYS
    &CELL
      ABC [angstrom] 10.0 10.0 10.0
      PERIODIC NONE
    &END CELL
    &TOPOLOGY
      COORD_FILE_NAME h2o.xyz
      COORD_FILE_FORMAT XYZ
      &CENTER_COORDINATES
      &END CENTER_COORDINATES
    &END TOPOLOGY
    &KIND O
      BASIS_SET DZVP-MOLOPT-GTH
      POTENTIAL GTH-PBE-q6
    &END KIND
    &KIND H
      BASIS_SET DZVP-MOLOPT-GTH
      POTENTIAL GTH-PBE-q1
    &END KIND
  &END SUBSYS
&END FORCE_EVAL