title: Integral equation study of an ideal Ising mixture.
abstract: We construct an integral equation scheme for magnetic binary mixtures of an ideal soft-core Ising fluid and a soft-sphere fluid by mapping the system onto an equivalent nonmagnetic ternary mixture. We apply the multicomponent Ornstein-Zernike equation together with a closure relation based on the soft mean spherical approximation and a field constraint for the Ising fluid component. Phase coexistence curves are calculated both by directly evaluating the chemical potentials via the bridge function, and by using a Maxwell-like construction which is derived in the text. Our results are compared to Monte Carlo data obtained earlier, and we find that the second method yields a much better agreement with the simulations.
authors.affiliation: Institute for Theoretical Physics, Linz University, A-4040 Linz, Austria.
authors.forename: W
authors.initials: W
authors.lastname: Fenz
authors.forename: I P
authors.initials: IP
authors.lastname: Omelyan
authors.forename: R
authors.initials: R
authors.lastname: Folk