Isomorphism of critical vaporization phenomena in pure substances and binary mixtures

By integration with respect to a noncritical order parameter (the concentration of the mixture), a model Hamiltonian of Landau-Ginzburg type for a binary mixture is reduced to the Hamiltonian of a single-component fluid. The conditions under which this isomorphism is possible are considered. It is shown that taking into account fluctuations of a critical order parameter (the total density of the mixture) by Wilson's approximate method leads, in an approximation linear in ( =4 – d; d is the dimensionality of the space), to the renormalization of the Hamiltonian parameters and to values of the critical indices, , , , which for = 1 are close to those observed experimentally.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 35–40, November, 1976.