# https://doi.org/10.1016/j.jnucmat.2005.01.001
    # https://doi.org/10.1557/opl.2012.520
    # https://doi.org/10.1103/PhysRevB.85.184103
    &FORCEFIELD
      ZBL_SCATTERING off
      &SHELL O
        CORE_CHARGE  +1.186267
        SHELL_CHARGE -3.186267
        MASS_FRACTION 0.1
        K2_SPRING [eV*Angstrom^-2] 70.824
        K4_SPRING [eV*Angstrom^-4] 849.888
        MAX_DISTANCE [Angstrom] 0.5
      &END SHELL
      &SHELL U
        CORE_CHARGE  -2.84
        SHELL_CHARGE +6.84
        MASS_FRACTION 0.01
        K2_SPRING [eV*Angstrom^-2] 171.556
        K4_SPRING [eV*Angstrom^-4] 2058.672
        MAX_DISTANCE [Angstrom] 0.5
      &END SHELL
      &NONBONDED
        &BUCK4RANGES
          ATOMS O O
          A [eV] 20908.03
          B [Angstrom^-1] 1/0.129629
          C [eV*Angstrom^6] 229.04
          R1 [Angstrom] 1.17
          R2 [Angstrom] 1.62
          R3 [Angstrom] 2.84
          # POLY1 [eV] 4204.472427467161 -7959.112702279119 6021.074988330987 -2270.766871550818 426.319753380798 -31.850801875744
          # POLY2 [eV] 6.734634669569 -6.692698089020 1.656245757939 -0.122636741736
          RCUT [Angstrom] 10.4
        &END BUCK4RANGES
        &WILLIAMS
          ATOMS O U
          A [eV] 844.41
          B [Angstrom^-1] 1/0.425243
          C [eV*Angstrom^6] 0.0
          RCUT [Angstrom] 10.4
        &END WILLIAMS
        &WILLIAMS
          ATOMS U U
          A [eV] 0.0
          B [Angstrom^-1] 0.0
          C [eV*Angstrom^6] 0.0
          RCUT [Angstrom] 10.4
        &END WILLIAMS
      &END NONBONDED
      &SPLINE
        EMAX_ACCURACY [hartree] 0.02
        EMAX_SPLINE [hartree] 1.0E4
        EPS_SPLINE [hartree] 1.0E-7
        R0_NB [Angstrom] 0.1
      &END SPLINE
    &END FORCEFIELD