Continuous surface charge polarizable continuum models of solvation. I. General formalism
Continuous surface charge polarizable continuum models of solvation. I. General formalism
复制标题
DOI：
10.1063/1.3359469
复制
发表时间：
2010-03-21
影响因子：
4.4
通讯作者：
Frisch, Michael J.
中科院分区：
文献类型：
--
作者：
Scalmani, Giovanni;Frisch, Michael J.
连续溶剂化模型是有吸引力的，因为它们提供了简化而准确的描述溶剂对溶质的影响，无论是量子力学或经典方法描述。极化连续模型（PCM）系列的溶剂化模型是最广泛使用的，虽然他们的应用受到阻碍的不连续性和奇异性所产生的离散化的积分方程在溶质-溶剂界面。在这方面的贡献，我们介绍了一个连续的表面电荷（CSC）的方法，导致一个光滑和强大的PCM模型的形式主义。我们从十多年前由约克和Karplus提出的方案开始，我们以各种方式将其推广，包括扩展到解析二阶导数原子位置。我们提出了一个最佳的离散表示所需的确定表观表面电荷的积分算子。我们实现了“模型”和“腔”之间的明确分离，再加上简单的概括现代积分代码，是所有需要的PCM模型的可扩展和有效的实施。根据这种方法，我们现在能够引入溶剂对能量，结构和振动频率（相对于原子坐标的分析一阶和二阶导数），磁性（相对于磁场使用GIAO的导数）的影响，以及在计算中更复杂的性质，如频率依赖的拉曼活性，振动圆二色性和拉曼光学活性。
Continuum solvation models are appealing because of the simplified yet accurate description they provide of the solvent effect on a solute, described either by quantum mechanical or classical methods. The polarizable continuum model (PCM) family of solvation models is among the most widely used, although their application has been hampered by discontinuities and singularities arising from the discretization of the integral equations at the solute-solvent interface. In this contribution we introduce a continuous surface charge (CSC) approach that leads to a smooth and robust formalism for the PCM models. We start from the scheme proposed over ten years ago by York and Karplus and we generalize it in various ways, including the extension to analytic second derivatives with respect to atomic positions. We propose an optimal discrete representation of the integral operators required for the determination of the apparent surface charge. We achieve a clear separation between "model" and "cavity" which, together with simple generalizations of modern integral codes, is all that is required for an extensible and efficient implementation of the PCM models. Following this approach we are now able to introduce solvent effects on energies, structures, and vibrational frequencies (analytical first and second derivatives with respect to atomic coordinates), magnetic properties (derivatives with respect of magnetic field using GIAOs), and in the calculation more complex properties like frequency-dependent Raman activities, vibrational circular dichroism, and Raman optical activity.