Title: NON-UNIVERSAL CRITICAL PROPERTIES OF A SYMMETRICAL BINARY FLUID MIXTURE
Author(s): O.V.Patsahan, R.S.Melnyk, M.P.Kozlovskii (Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii Str., 79011 Lviv, Ukraine)

We study non-universal critical properties of a symmetrical mixture using the recently proposed approach and the method of layer-by-layer integration of a partition function. Both the gas-liquid critical point properties (temperature and density) and the fluid-fluid demixing temperature of a symmetrical hard-sphere square-well mixture are calculated depending on its microscopic parameters: the parameter $r$ measuring the strength of interactions between the particles of dissimilar and similar species and the parameter $\lambda$ measuring the width of the potential well.

Key words: non-universal critical properties, gas-liquid critical point, fluid-fluid demixing, binary mixture
PACS: 05.70.Fh, 05.70.Jk, 65.10.+h