&FORCE_EVAL
  METHOD FIST
  &MM
    &FORCEFIELD
      &BEND
        ATOMS H O H
        K 0.
        THETA0 1.8
      &END BEND
      &BOND
        ATOMS O H
        K 0.
        R0 1.8
      &END BOND
      &CHARGE
        ATOM O
        CHARGE -0.8476
      &END CHARGE
      &CHARGE
        ATOM H
        CHARGE 0.4238
      &END CHARGE
      &NONBONDED
        &LENNARD-JONES
          atoms O O
          EPSILON 78.198
          SIGMA 3.166
          RCUT 11.4
        &END LENNARD-JONES
        &LENNARD-JONES
          atoms O H
          EPSILON 0.0
          SIGMA 3.6705
          RCUT 11.4
        &END LENNARD-JONES
        &LENNARD-JONES
          atoms H H
          EPSILON 0.0
          SIGMA 3.30523
          RCUT 11.4
        &END LENNARD-JONES
      &END NONBONDED
    &END FORCEFIELD
    &POISSON
      &EWALD
        EWALD_TYPE ewald
        ALPHA .44
        GMAX 21
      &END EWALD
    &END POISSON
  &END MM
  &SUBSYS
    &CELL
      ABC 24.955 24.955 24.955
    &END CELL
    &COORD
  O         1.1274189403        0.0203885010       -0.0645225025  H2O
  H         1.7150615769        0.6494419975        0.4443670104  H2O
  H         1.2854004748       -0.9144223765        0.2535516481  H2O
  O        -2.1831607819       -0.0618324395       -0.0051722266  H2O
  H        -2.6230347760        0.3642527369        0.7853737928  H2O
  H        -1.4926282224        0.5585794002       -0.3769984099  H2O
    &END COORD
    &COLVAR
      &DISTANCE
        ATOMS 1 4
      &END DISTANCE
    &END COLVAR
  &END SUBSYS
&END FORCE_EVAL
&GLOBAL
  PROJECT metadyn3
  RUN_TYPE md
  PRINT_LEVEL LOW
&END GLOBAL
&MOTION
  &CONSTRAINT
    &G3X3
      DISTANCES 1.8897268 1.8897268 3.0859239
      MOLECULE 1
      ATOMS 1 2 3
    &END G3X3
  &END CONSTRAINT
  &FREE_ENERGY
    METHOD METADYN
    &METADYN
      &METAVAR
        COLVAR 1
        SCALE 1.0
        &WALL
          POSITION 5.0
          TYPE QUARTIC
          &QUARTIC
            DIRECTION WALL_MINUS
            K 0.0001
          &END QUARTIC
        &END WALL
      &END METAVAR
      &PRINT
        &COLVAR OFF
        &END COLVAR
      &END PRINT
    &END METADYN
  &END FREE_ENERGY
  &MD
    ENSEMBLE NVE
    STEPS 50
    TIMESTEP 2.5
    TEMPERATURE 298
  &END MD
&END MOTION
