In the implicit solvent models of electrolytes (such as the primitive model (PM)), the ions are modeled as point charges in the centers of spheres (hard spheres in the case of the PM). The surfaces of the spheres are not polarizable which makes these models appropriate to use in computer simulations of electrolyte systems where these ions do not leave their host dielectrics. The same assumption makes them inappropriate in simulations where these ions cross dielectric boundaries because the interaction energy of the point charge with the polarization charge induced on the dielectric boundary diverges. In this paper, we propose a procedure to treat the passage of such ions through dielectric interfaces with an interpolation method. Inspired by the “bubble ion” model (in which the ion's surface is polarizable), we define a space-dependent effective dielectric coefficient, ε eff (>r), for the ion that overlaps with the dielectric boundary. Then, we replace the “bubble ion” with a point charge that has an effective charge q∕ε eff (>r) and remove the portion of the dielectric boundary where the ion overlaps with it. We implement the interpolation procedure using the induced charge computation method [D. Boda, D. Gillespie, W. Nonner, D. Henderson, and B. Eisenberg, Phys. Rev. E 69, 046702 (2004)]. We analyze the various energy terms using a spherical ion passing through an infinite flat dielectric boundary as an example.
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机译：在电解质的隐式溶剂模型（例如原始模型（PM））中，将离子建模为球体中心（在PM中为硬球体）中的点电荷。球体的表面是不可极化的，这使得这些模型适合用于电解质系统的计算机模拟中，这些离子不会离开其主体电介质。相同的假设使它们不适用于这些离子跨过电介质边界的仿真，因为点电荷与在电介质边界上感应的极化电荷的相互作用能会发散。在本文中，我们提出了一种使用插值方法处理此类离子通过介电界面的程序。受“气泡离子”模型（离子表面可极化）的启发，我们定义了与介电边界重叠的离子的空间相关有效介电系数εeff（> r ） 。然后，我们用具有有效电荷q ∕εeff（> r ）的点电荷替换“气泡离子”，并去除电介质边界中与离子重叠的部分。我们使用感应电荷计算方法[D。 Boda，D.Gillespie，W.Nonner，D.Henderson和B.Eisenberg，物理学。 E 69，046702（2004）。我们以穿过无限平面介电边界的球形离子为例分析各种能量项。
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