# SPC/E water
    # H. J. C. Berendsen, J. R. Grigera, and T. P. Straatsma, J. Phys. Chem. 91, 6269 (1987)
    # https://doi.org/10.1021/j100308a038
    # Note: This force field requires a correpsonding &G3X3 constraint section
    #       in &MOTION / &CONSTRAINT
    #       Alternatively, an unconstrained flexible variant of this force field can be defined
    #       by setting the K parameters in the sections &BEND and &BOND to non-zero values.
    #       Usage examples can be found in the folder cp2k/tests/Fist/regtest-water/.
    &FORCEFIELD
      &BEND
        ATOMS HW OW HW
        K [kcalmol*rad^-2] 0.0
        KIND harmonic
        THETA0 [deg] 109.47
      &END BEND
      &BOND
        ATOMS OW HW
        K [kcalmol*Angstrom^-2] 0.0
        KIND harmonic
        R0 [Angstrom] 1.000
      &END BOND
      &CHARGE
        ATOM OW
        CHARGE -0.8476
      &END CHARGE
      &CHARGE
        ATOM HW
        CHARGE +0.4238
      &END CHARGE
      &NONBONDED
        &LENNARD-JONES
          ATOMS HW HW
          EPSILON [kcalmol] 0.0
          SIGMA [Angstrom] 1.0
          RCUT [Angstrom] 12.0
        &END LENNARD-JONES
        &LENNARD-JONES
          ATOMS OW HW
          EPSILON [kcalmol] 0.0
          SIGMA [Angstrom] 1.0
          RCUT [Angstrom] 12.0
        &END LENNARD-JONES
        &LENNARD-JONES
          ATOMS OW OW
          EPSILON [kJmol] 0.65016958
          SIGMA [Angstrom] 3.16555789
          RCUT [Angstrom] 12.0
        &END LENNARD-JONES
      &END NONBONDED
    &END FORCEFIELD