The equilibrium lattice constants for various rock salt structure type compounds were predicted by an ab-initio pseudopotential method adapted in the Vienna Ab-initio Simulation Program (VASP), and the values were compared with the experimental lattice constants found in the literature to check the transferability of the pseudopotential of each atom. The results clearly indicate that a well-transferable pseudopotential is essential to predict the material properties of complex ionic systems consisting of many different kinds of atoms.

Keywords: ab-initio method, DFT, ultrasoft pseudopotential, transferability