STRUCTURAL STABILITY OF ATOMIC ENVIRONMENT TYPES IN AB INTERMETALLIC COMPOUNDS

A simple model is presented for studying the structural stability of a tomic environments of AB intermetallic compounds. The relative stabili ty of the four most common atomic environment types (AETs) has been sy stematically calculated within a tight-binding model. The calculated t hree-dimensional structure map using the difference of the valence ele ctron orbital energy of an atom, Delta E, the distance between atoms, d, and the average number of electron per atoms, (N) over bar, shows g ood agreement with the corresponding semi-empirical quantum structural diagram (QSD). This three-dimensional structure map is for the global understanding of structural trends shown in d versus Delta E plots at constant (N-V) over bar, (with constant power indexes lambda of the r epulsive potential term) and in Delta E versus (N) over bar plots at c onstant d and lambda. The approach used in this paper provides a possi bility of classifying intermetallic compounds into AET with systematic al tight-binding calculation by extending to different kind of interac tion systems, which might be taken as one step towards setting up a kn owledge base of crystal structure prediction for materials design.