Improved calculation of rotational diffusion and intrinsic viscosity of bead models for macromolecules and nanoparticles
Improved calculation of rotational diffusion and intrinsic viscosity of bead models for macromolecules and nanoparticles
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DOI：
10.1021/jp0647941
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发表时间：
2007-02-08
影响因子：
3.3
通讯作者：
Ortega, A.
中科院分区：
文献类型：
--
作者：
Garcia de la Torre, J.;del Rio Echenique, G.;Ortega, A.
珠子模型流体动力学特性的传统 Kirkwood-Riseman 计算对于具有少量珠子或当一个珠子占主导地位的模型给出了旋转量和特性粘度的异常结果。原因是珠子被视为摩擦点。这可以通过引入在珠间距离的 0 阶和 -3 阶常规处理中被忽略的项来补救。另一种策略是立方替换，其中每个珠子都被迷你珠子的立方阵列替换。这些程序需要计算过载，在特性粘度的情况下，可以使用由于珠子的非零体积而进行校正的估计来避免计算过载。我们已经发现如何根据模型的几何形状来估计这种校正，并且其应用产生的结果在典型实验误差范围内。
The conventional Kirkwood-Riseman calculation of the hydrodynamic properties of bead models gives abnormal results for rotational quantities and the intrinsic viscosities for models with a few beads or when one bead is dominant. The reason is that beads are treated as point sources of friction. This can be remedied by introducing terms that are neglected in the conventional treatment of orders 0 and -3 in interbead distances. An alternative strategy is the cubic substitution in which each bead is replaced by a cubic array of minibeads. These procedures require a computational overload that, in the case of the intrinsic viscosity, can be avoided using an estimate of the correction due to the nonzero volume of the beads. We have found how such a correction can be estimated from the geometry of the model, and its application yields results that are within the range of typical experimental errors.