Gapinski J, Patkowski A, Banchio A J, Holmqvist P, Meier G, Lettinga M P, Nägele G
Institute of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland.
J Chem Phys. 2007 Mar 14;126(10):104905. doi: 10.1063/1.2538891.
The authors present a joint experimental-theoretical study of collective diffusion properties in aqueous suspensions of charge-stabilized fluorinated latex spheres. Small-angle x-ray scattering and x-ray photon correlation spectroscopy have been used to explore the concentration and ionic-strength dependence of the static and short-time dynamic properties including the hydrodynamic function H(q), the wave-number-dependent collective diffusion coefficient D(q), and the intermediate scattering function over the entire accessible range. They show that all experimental data can be quantitatively described and explained by means of a recently developed accelerated Stokesian dynamics simulation method, in combination with a modified hydrodynamic many-body theory. In particular, the behavior of H(q) for de-ionized and dense suspensions can be attributed to the influence of many-body hydrodynamics, without any need for postulating hydrodynamic screening to be present, as it was done in earlier work. Upper and lower boundaries are provided for the peak height of the hydrodynamic function and for the short-time self-diffusion coefficient over the entire range of added salt concentrations.
作者们展示了一项关于电荷稳定的氟化乳胶球水悬浮液中集体扩散性质的联合实验与理论研究。小角X射线散射和X射线光子相关光谱已被用于探究静态和短时间动态性质对浓度和离子强度的依赖性，这些性质包括流体动力学函数H(q)、波数相关的集体扩散系数D(q)，以及在整个可及范围内的中间散射函数。他们表明，所有实验数据都可以通过一种最近开发的加速斯托克斯动力学模拟方法，并结合一种修正的流体动力学多体理论进行定量描述和解释。特别是，去离子化和致密悬浮液中H(q)的行为可归因于多体流体动力学的影响，无需像早期工作那样假设存在流体动力学屏蔽。在整个添加盐浓度范围内，给出了流体动力学函数峰值高度和短时间自扩散系数的上下限。
