The Pseudopotential Method and the Problem of Ordering in Alloys. I. Pairwise Interaction

Abstract
The thermodynamic statistical theory of ordering by Khachaturyan is formulated in terms of the pseudopotential method of second order perturbation theory. The general quantity of the theory, V(k) – the Fourier transform of alloying potential – is expressed through the pseudopotentials of the ions constituting the alloy. As an example the CaBa system is considered and an a‐priori procedure of determining the equilibrium superstructure and its thermodynamic characteristics is demonstrated. The difficulties and limitations of the theory are discussed.