Integral equation theory for polyelectrolyte solutions containing counterions and coions

Integral equations for equilibrium correlation functions of a three-component polyelectrolyte solution (polyions, counterions, coions) are solved numerically. Various pair correlation functions and structure factors are investigated. It is shown that added salt screens the Coulomb interaction between the negatively charged polyions. The comparison of the calculated polyion-polyion partial structure factor with experimental results of light scattering experiments on tobacco mosaic virus in a solution with added salt exhibits good agreement. Moreover, the counterion condensation on rodlike polyions is studied by means of pair correlation functions. (C) 2000 American Institute of Physics. [S0021-9606(00)50601-1].