A Study of the Variation of Monovacancy Formation Energy with the Parameter of Ashcroft's Potential and Different Exchange and Correlation Functions for Some Group-IIa and Group-VIII FCC Metals in the Active Divalent State

Abstract

Graphs of monovacancy formation energy ( ) versus the parameter, , of Ashcroft's empty-core model potential (AECMP) and nine different exchange and correlation functions (ECF) are shown for two different group-IIa divalent fcc metals (Ca and Sr) and seven group-VIII divalent fcc metals in an active valence state (γ-Fe, β-Co, Rh, Ir, Ni, Pd and Pt). The criterion used is that is greater than the Bohr radius. There is a systematic increase and decrease in the fitted value of , and the calculated value of , respectively, in going from one ECF to other, as follows: Sham<K-K<G-V<Kle<Harr<V-S<Hub<Tay<M-D for group-IIa face-centered cubic metals and K-K<G-V<Sham<…..<Tay<Hub<M-D for group-VIII face-centered cubic metals; with a slight variation in between. It should be noted that the inherent simplicity of AECMP makes it difficult to have a universal parameter for all types of atomic property calculations.