A description of the effect of short range ordering in the compound energy formalism

The current state of the compound energy formalism (CEF) to model ordering and the technique to handle short range ordering (SRO) were discussed. Although there are some methods which allow better treatment for SRO, such as the cluster variation method (CVM) or the Monte Carlo method (MC), these methods are difficult to handle in multi-component systems because of their complexity. In the compound energy formalism, SRO is not explicitly described. However it is possible to take the contribution of SRO to the Gibbs free energy into account through the reciprocal parameter, which has the same concentration dependency as DeltaG(m)(SRO). Introducing the reciprocal parameter of the form, L-i,L-j:i,L-j for the two sublattice model and L-i,L-j:i,L-j:*:* for the four sublattice model, one can satisfactorily describe the contribution of SRO to the Gibbs free energy in the CEF. (C) 2004 Elsevier Ltd. All rights reserved.