An effective partial charge model for bulk and surface properties of cubic ZrO2, Y2O3 and yttrium-stabilised zirconia

In this work a newly parametrised Coulomb plus Buckingham potential formulation for cubic ZrO2, Y2O3 and yttrium-stabilised zirconia (YSZ) is presented. The density and pair distributions obtained for neat ZrO2 and Y2O3 under ambient conditions are in excellent agreement with experimental data, while the vibrational power spectra are highly similar compared to those obtained via ab initio molecular dynamics simulations at the PBEsol level. In addition, it is shown that the use of effective partial charges has several advantages compared to interaction potentials employing the oxidation states in the evaluation of the coulombic interactions: (i) the diffusion coefficient and the associated activation energy of oxygen ions evaluated for YSZn (n = 4 to 12) display the best agreement with experimental data; (ii) no unphysical reorganisation of the interface and the bulk are observed in simulations of the (110) and (111) surfaces of cubic ZrO2 and Y2O3, while due to the strong coulombic contributions in the case of the tested full-charge models a pronounced restructuring of the interface and the bulk is observed in the ZrO2 case, and (iii) the use of effective partial charges ensures compatibility with existing solvent models and force-fields for the treatment of molecular compounds.