Allahyarov E, Löwen H
Institut für Theoretische Physik II: Weiche Materie, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany. Department of Physics, Case Western Reserve University, Cleveland, OH 44106, USA. Joint Institute for High Temperatures, Russian Academy of Sciences, Moscow, Russia.
J Phys Condens Matter. 2009 Oct 21;21(42):424117. doi: 10.1088/0953-8984/21/42/424117. Epub 2009 Sep 30.
Based on primitive model computer simulations with explicit microions, we calculate the effective interactions in a binary mixture of charged colloids with species A and B for different size and charge ratios. An optimal pairwise interaction is obtained by fitting the many-body effective forces. This interaction is close to a Yukawa (or Derjaguin-Landau-Verwey-Overbeek (DLVO)) pair potential but the AB cross-interaction is different from the geometric mean of the two direct AA and BB interactions. As a function of charge asymmetry, the corresponding nonadditivity parameter is first positive, then significantly negative and is then positive again. We finally show that an inclusion of nonadditivity within an optimal effective Yukawa model gives better predictions for the fluid pair structure than DLVO theory.
基于带有显式微离子的原始模型计算机模拟，我们计算了不同尺寸和电荷比的A、B两种带电胶体二元混合物中的有效相互作用。通过拟合多体有效力获得了最优的成对相互作用。这种相互作用接近 Yukawa（或 Derjaguin-Landau-Verwey-Overbeek（DLVO））对势，但AB交叉相互作用不同于两个直接的AA和BB相互作用的几何平均值。作为电荷不对称性的函数，相应的非加和性参数首先为正，然后显著为负，之后又再次为正。我们最终表明，在最优有效 Yukawa 模型中纳入非加和性，比 DLVO 理论能更好地预测流体对结构。
