Falcón-González José Marcos, Contreras-Aburto Claudio, Lara-Peña Mayra, Heinen Marco, Avendaño Carlos, Gil-Villegas Alejandro, Castañeda-Priego Ramón
Unidad Profesional Interdisciplinaria de Ingeniería, Campus Guanajuato, Instituto Politécnico Nacional, Av. Mineral de Valenciana No. 200, Col. Fraccionamiento Industrial Puerto Interior, C.P. 36275 Silao de la Victoria, Guanajuato, Mexico.
Facultad de Ciencias en Física y Matemáticas, Universidad Autónoma de Chiapas, 29050 Tuxtla Gutiérrez, Mexico.
J Chem Phys. 2020 Dec 21;153(23):234901. doi: 10.1063/5.0033561.
The Ewald method has been the cornerstone in molecular simulations for modeling electrostatic interactions of charge-stabilized many-body systems. In the late 1990s, Wolf and collaborators developed an alternative route to describe the long-range nature of electrostatic interactions; from a computational perspective, this method provides a more efficient and straightforward way to implement long-range electrostatic interactions than the Ewald method. Despite these advantages, the validity of the Wolf potential to account for the electrostatic contribution in charged fluids remains controversial. To alleviate this situation, in this contribution, we implement the Wolf summation method to both electrolyte solutions and charged colloids with moderate size and charge asymmetries in order to assess the accuracy and validity of the method. To this end, we verify that the proper selection of parameters within the Wolf method leads to results that are in good agreement with those obtained through the standard Ewald method and the theory of integral equations of simple liquids within the so-called hypernetted chain approximation. Furthermore, we show that the results obtained with the original Wolf method do satisfy the moment conditions described by the Stillinger-Lovett sum rules, which are directly related to the local electroneutrality condition and the electrostatic screening in the Debye-Hückel regime. Hence, the fact that the solution provided by the Wolf method satisfies the first and second moments of Stillinger-Lovett proves, for the first time, the reliability of the method to correctly incorporate the electrostatic contribution in charge-stabilized fluids. This makes the Wolf method a powerful alternative compared to more demanding computational approaches.
埃瓦尔德方法一直是分子模拟中对电荷稳定多体系统静电相互作用进行建模的基石。在20世纪90年代后期，沃尔夫及其合作者开发了一种描述静电相互作用长程性质的替代方法；从计算角度来看，该方法提供了一种比埃瓦尔德方法更高效、更直接的实现长程静电相互作用的方式。尽管有这些优点，但沃尔夫势在解释带电流体中静电贡献方面的有效性仍存在争议。为缓解这种情况，在本论文中，我们将沃尔夫求和方法应用于电解质溶液以及具有中等尺寸和电荷不对称性的带电胶体，以评估该方法的准确性和有效性。为此，我们验证了在沃尔夫方法中正确选择参数会得到与通过标准埃瓦尔德方法以及在所谓超网链近似下简单液体积分方程理论所得到的结果高度一致的结果。此外，我们表明用原始沃尔夫方法得到的结果确实满足由斯蒂林格 - 洛维特求和规则描述的矩条件，这些条件与德拜 - 休克尔区域中的局部电中性条件和静电屏蔽直接相关。因此，沃尔夫方法提供的解满足斯蒂林格 - 洛维特的一阶和二阶矩这一事实首次证明了该方法在正确纳入电荷稳定流体中静电贡献方面的可靠性。这使得沃尔夫方法与要求更高的计算方法相比成为一种强大的替代方法。
