The structure of binary mixtures of charged colloidal suspensions

Structural properties of mixtures of charged colloidal particles are studied by solving the Ornstein-Zernike equation together with the Rogers-Young closure relation. The partial radial distribution functions gij(r) are found to agree very well with results obtained from molecular dynamics simulations. From gij(r) partial structure factors Sij(k) are determined. They are used to obtain results for the experimentally accessible structure factor SM(k) and for the Bhatia-Thornton structure factors SNN(k), SCC(k) and SCC(k). The latter describe concentration ordering, charge ordering and their coupling. A systematic study of these quantities is presented as a function of relative composition of the two components. It is found that various features of SM(k), such as position and height of the main peak and its value at k = 0, change non-monotonously as a function of composition.