  The accurate description of iron oxides/water interfaces requires reliable
force field parameters that can be developed through the comparison with
sophisticated quantum mechanical calculations. Here a set of CLASS2 force field
parameters is optimized to describe the Fe-Owater cross interaction through
comparison with hybrid density functional theory (HSE06) calculations of the
potential energy function for a single water molecule adsorbed on the Fe3O4
(001) surface and with density functional tight binding (DFTB+U) molecular
dynamics simulations for a water tri-layer on the same surface. The performance
of the new parameters is assessed through the analysis of the number density
profile of a water bulk (12 nm) sandwiched between two magnetite slabs of large
surface area. Their transferability is tested for the water adsorption on the
curved surface of a spherical Fe3O4 nanoparticle of realistic size (2.5 nm).
