Derivation of interionic potentials using embedded quantum-mechanical clusters: Cation and anion impurities in MgO

The ICECAP methodology is used to derive interionic potentials of some cation and anion impurities in MgO, namely, Li⁺, Na⁺, K⁺, Be²⁺, H⁻, S²⁻, and O²⁻. Analysis is given of the defect energies obtained by using the derived impurity potentials. Based on the available experimental data, comparison is made to justify the reliability of the derived impurity potential for Be²⁺. The calculated activation energy for Be²⁺ diffusion comes out to be 1.54 eV as compared to the experimental value of 1.60 eV, which is considered to be very satisfactory.