title: Cluster formation in two-Yukawa fluids.
abstract: We present a different and efficient method for implementing the analytical solution of Ornstein-Zernike equation for two-Yukawa fluids in the mean spherical approximation. We investigate, in particular, the conditions for the formation of an extra low-Q peak in the structure factor, which we interpret as due to cluster formation in the two-Yukawa fluid when the interparticle potential is composed of a short-range attraction and a long-range repulsion. We then apply this model to interpret the small angle neutron scattering data for protein solutions at moderate concentrations and find out that the presence of a peak centered at Q=0 (zero-Q peak) besides the regular interaction peak due to charged proteins implies an existence of long-range attractive interactions besides the charge repulsion.
authors.affiliation: Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. yunliu@mit.edu
authors.forename: Yun
authors.initials: Y
authors.lastname: Liu
authors.forename: Wei-Ren
authors.initials: WR
authors.lastname: Chen
authors.forename: Sow-Hsin
authors.initials: SH
authors.lastname: Chen