Evaluation of cooperativity for phase transitions in two- and three-dimensional systems

摘要: Abstract Use of the so-called “cooperative unit” (readily obtainable from midpoint slope phase transition curves) is discussed for determination cluster sizes and cooperative interaction energies. This quantity has been commonly employed in a rather empirical way since its correct interpretation known only some special cases (linear systems, all-or-none transitions). It shown framework lattice model (Ising model) that unit may be interpreted terms correlation functions it defines an average corresponding to patch size as obtained scattering experiments. Relations between cooperativity parameter are given various lattices. Different types curves using simple analytical formalism, quasichemical approximation. Some important nonideality effects investigated which lead “smearing-out” first-order transitions.