Molecular dynamics simulations of aqueous electrolytes generally rely on empirical force fields, combining dispersion interactions—described by a truncated Lennard-Jones (LJ) potential—and electrostatic interactions—described by a Coulomb potential computed with a long-range solver. Recently, force fields using rescaled ionic charges [electronic continuum correction (ECC)], possibly complemented with rescaling of LJ parameters [ECC rescaled (ECCR)], have shown promising results in bulk, but their performance at interfaces has been less explored. Here, we started by exploring the impact of the LJ potential truncation on the surface tension of a sodium chloride aqueous solution. We show a discrepancy between the numerical predictions for truncated LJ interactions with a large cutoff and for untruncated LJ interactions computed with a long-range solver, which can bias comparison of force field predictions with experiments. Using a long-range solver for LJ interactions, we then show that an ionic charge rescaling factor chosen to correct long-range electrostatic interactions in bulk accurately describes image charge repulsion at the liquid–vapor interface, and the rescaling of LJ parameters in ECCR models—aimed at capturing local ion–ion and ion–water interactions in bulk— describes well the formation of an ionic double layer at the liquid–vapor interface. Overall, these results suggest that the molecular modeling of aqueous electrolytes at interfaces would benefit from using long-range solvers for dispersion forces and from using ECCR models, where the charge rescaling factor should be chosen to correct long-range electrostatic interactions.

中文翻译：

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界面处电解质水溶液的分子模型：远程分散力和离子电荷重新缩放的影响。

水性电解质的分子动力学模拟通常依赖于经验力场，将分散的相互作用（由截短的Lennard-Jones（LJ）电位描述）和静电相互作用（由用长距离求解器计算的库仑电位描述）结合在一起。最近，使用重标定的离子电荷[电子连续谱校正（ECC）]的力场，可能与LJ参数的标定[ECC重标的（ECCR）]相辅相成，已显示出令人鼓舞的结果，但在界面上的性能却很少得到研究。在这里，我们开始探讨LJ电位截断对氯化钠水溶液表面张力的影响。我们显示了截断的LJ相互作用具有大截止值的数值预测与使用长距离求解器计算的未截断的LJ相互作用的数值预测之间的差异，这可能会使力场预测与实验的比较产生偏差。使用用于LJ相互作用的长距离求解器，我们然后表明选择用来校正本体中的长距离静电相互作用的离子电荷缩放因子可以准确地描述液-气界面处的图像电荷排斥力，以及ECCR模型中LJ参数的缩放旨在捕获大量的局部离子-离子和离子-水相互作用-很好地描述了在液-气界面处离子双层的形成。总体，