A rigid lattice gas model of solid-liquid, liquid-gas, and solid-gas transformations is proposed. The total free energy is separated into a lattice part and a vibrational correction part. It is reported that the vibrational part plays an important role in obtaining the gas, liquid and solid...

Investigating honeycomb and triangular simple spin-12 Ising model ferromagnets, exact algebraic systems of linear identities are developed containing the spontaneous magnetization and other odd-number correlations where the coefficients depend upon the interaction parameters. Aided by...