Nonadditivity in Molecular Interactions

该项目由理论和计算化学项目支持，将使用第一性原理从头算量子力学方法研究各种化学系统中分子间相互作用的非可加性。弱分子间力和相互作用是研究凝聚态物质性质的关键。在这样的环境中，一对分子之间的相互作用会影响它们各自与第三个分子相互作用的方式。因此，分子间相互作用的成对可加性假设是一个很差的近似。目前大多数模拟凝聚相反应的方法要么完全忽略相互作用的不可加性，要么试图以一种非常粗糙的方式包括它，并在相互作用势中混入一些错误。关于非可加性的一个常见误解是它起源于单一来源。然而，在现实中，它产生于许多根本不同的物理现象。本理论研究旨在阐明导致非加性的所有效应，并将这些效应分解为标记为分散、诱导和交换的成分。这样的分析将导致在基本层面上对这些影响有更好的了解。这项工作将导致许多明确包括多体效应的分析势的发展，因此适用于凝聚态的模拟。以及簇的性质。

This project supported by the Theoretical and Computational Chemistry program will study non-additivity of intermolecular interactions in a variety of chemical systems using first principles ab-initio quantum mechanical methods. Weak intermolecular forces and interactions are of key importance in studies of the properties of matter in condensed phases. In such an environment, the interaction in a pair of molecules affects the ways each of them interacts with a third. The assumption of pairwise additivity of intermolecular interactions is thus a very poor approximation. Most current means of simulating condensed phase reactions either disregard non-additivity of interactions entirely, or attempt to include it in a very crude manner, mixed together with a number of errors in the interaction potentials. One common misconception about non-additivity is that it originates from a single source. However, in reality it arises from a number of fundamentally different physical phenomena. This theoretical research is aimed at elucidating all of the effects responsible for non-additivity and to break these down into components which are labeled dispersion, induction and exchange. Such an analysis will lead to an improved understanding of these effects on a fundamental level. This work will result in the development of a number of analytical potentials which explicitly include many-body effects and are thus suitable for simulations of condensed phases. as well as properties of clusters.