Cluster Sums for Lattice Gases with Second Nearest Neighbour Interactions. III. Three-Dimensional Simple Cubic Lattice

抄録

The exact expressions for the volume-dependent cluster sums (composed of four or less molecules) for the three-dimensional simple cubic lattice gas (in a cube-shaped vessel) with nearest and second nearest neighbour interactions are obtained. The detailed behaviour of the cluster sums for the simple cubic lattice gas as functions of the volume of the vessel is investigated for the case when the nearest neighbour interaction is repulsive and the second nearest neighbour interaction is attractive. On the basis of their behaviour, the condensation phenomenon of such a lattice gas is discussed by applying Ikeda’s theory of condensation of systems satisfying the G-condition.