(508b) Accurate Simulation of Oxides and Hydroxides up to the Large Nanometer Scale

The simulation of oxides, mixed oxides, and hydroxides is important to guide in the design of cement, ceramics, and glasses. Here we introduce an extension of the Interface force field (IFF) for several oxides and hydroxides (NiO, α-Fe₂O₃, α-Cr₂O₃, α-Al₂O₃, SiO₂, CaO, Ni(OH)₂ and Ca(OH)₂) using a nonbonded-only potential that involves Coulomb and Lennard-Jones terms. Care is taken that the atomic charges remain close to verifiable internal dipole moments even though covalent bonding contributions are disregarded. The non-bonded models are inherently reactive, enabling changes in morphology and defects. All models achieve quantitative agreement with experiment in lattice parameters (<1% deviation) and in bulk modulus (<10% deviation). They are fully compatible with existing parameters for other oxides, metals, solvents, and polymers following the IFF protocol. The parameters are available using both 12-6 and 9-6 Lennard-Jones potentials to achieve compatibility with CHARMM, CVFF, AMBER, OPLS-AA, PCFF, and COMPASS.