Department of Chemistry, The Ohio State University, Columbus, Ohio 43210, USA.
J Chem Phys. 2010 Dec 28;133(24):244111. doi: 10.1063/1.3511297.
Polarizable continuum models (PCMs) are a widely used family of implicit solvent models based on reaction-field theory and boundary-element discretization of the solute/continuum interface. An often overlooked aspect of these theories is that discretization of the interface typically does not afford a continuous potential energy surface for the solute. In addition, we show that discretization can lead to numerical singularities and violations of exact variational conditions. To fix these problems, we introduce the switching/Gaussian (SWIG) method, a discretization scheme that overcomes several longstanding problems with PCMs. Our approach generalizes a procedure introduced by York and Karplus [J. Phys. Chem. A 103, 11060 (1999)], extending it beyond the conductor-like screening model. Comparison to other purportedly smooth PCM implementations reveals certain artifacts in these alternative approaches, which are avoided using the SWIG methodology. The versatility of our approach is demonstrated via geometry optimizations, vibrational frequency calculations, and molecular dynamics simulations, for solutes described using quantum mechanics and molecular mechanics.
极化连续体模型（PCM）是一种广泛使用的隐溶剂模型，基于反应场理论和溶质/连续体界面的边界元离散化。这些理论中一个经常被忽视的方面是，界面的离散化通常不能为溶质提供连续的势能表面。此外，我们还表明，离散化可能导致数值奇点和精确变分条件的违反。为了解决这些问题，我们引入了切换/高斯（SWIG）方法，这是一种克服 PCM 中几个长期存在问题的离散化方案。我们的方法推广了 York 和 Karplus 引入的一种方法[J. Phys. Chem. A 103, 11060 (1999)]，将其扩展到了导体相似屏蔽模型之外。与其他据称平滑的 PCM 实现相比，在使用 SWIG 方法时可以避免这些替代方法中的某些伪影。通过使用量子力学和分子力学描述的溶质进行几何优化、振动频率计算和分子动力学模拟，展示了我们方法的多功能性。
