A rigid-ion potential based on the Born model of ionic solids to describe the potential energy of CeO2 systems. The energy between two ions is calculated by partitioning the energy into long-range Coulombic interactions and short-range interactions that approximate Pauli repulsions and van der Waal’s attractions between ions. The short-range term used is the Buckingham potential. The Ce-Ce interactions are considered to be purely coulombic due to their small radii compared with anions.