Journal of Physical Studies 9(3), 253–260 (2005) DOI: https://doi.org/10.30970/jps.09.253 THERMODYNAMICS OF ISING MODEL WITHIN CLUSTER EXPANSION METHOD R. R. Levitskii, S. I. Sorokov, O. R. Baran Institute for Condensed Matter Physics, 1 Svientsitskii St., Lviv, UA-79011, Ukraine, e-mail: ost@icmp.lviv.ua

For the Ising model the cluster expansion on the basis of a two-particle cluster is performed up to terms of the fourth-order in bonds. For a square lattice different orders of the cluster expansion are tested in a wide temperature range. The obtained results are compared with those of a four-particle cluster approximation at different forms of lattice division into clusters.

PACS number(s): 75.10.Hk

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