Rescaled Mean Spherical Approximation for Colloidal Mixtures

In this work, the resealed mean spherical approximation (RMSA) for colloidal mixtures interacting via a DLVO-type potential is developed, and its application to suspensions of highly charged macroions is illustrated. For this purpose we introduce a simple scheme to solve the mean spherical approximation (MSA) for Yukawa mixtures with factorized coupling parameters. This scheme consists of the mapping of the Yukawa system onto a corresponding primitive model system. Such a correspondence is used as a device for the calculation of the static structure functions of the original Yukawa mixture. Within this scheme, a straightforward implementation of the resealing procedure is performed, which allows for the calculation of partial structure factors in strongly interacting mixtures. The resealing procedure we use is an extension of that introduced by Hansen and Hayter for monodisperse suspensions. The structure factors obtained with the resealed mean spherical approximation compare well with computer simulation results. The advantages and limitations of the RMSA are also discussed in some detail.