Solvation Role on Kinetic Processes in Solution

Harold Friedman和Fernando Raineri得到了理论和计算化学计划的资助，他们使用积分方程式技术和分子动力学模拟的组合来了解复杂分子在各种溶剂环境中的溶剂化过程的结构、能量和动力学方面。他们发展了替代哈密顿理论，该理论采用重整化的线性响应理论来描述溶质时变场中溶剂的非平衡分布函数。该理论已被应用于一些较简单的系统，并用分子动力学模拟进行了验证。在下一阶段的研究中，将特别强调电子转移反应和键断裂/成键反应。替代哈密顿理论将被扩展到包括多阶矩、溶质排除体积和氢键效应等高阶效应。他们还计划对物理有机化学家使用的参数进行分子解释，以量化亲核溶剂在溶液中脂族卤化物的溶剂分解中的辅助作用。这项研究项目的目的是改进根据分子组成之间的相互作用来解释溶液的可测量性质的方式。这对离子溶液来说尤其具有挑战性，因为离子电荷之间的长范围作用力强烈地影响着可测量的性质和将它们与分子模型联系起来所需的数学工具。Friedman和Raineri的工作应该为溶剂化的机制和动力学提供基本的分子洞察。

Harold Friedman and Fernando Raineri are supported by a grant from the Theoretical and Computational Chemistry Program to use a combination of integral equation techniques and molecular dynamics simulations to understand the structural, energetic and dynamical aspects of the solvation of complex molecules in a variety of solvent environments. They have developed a Surrogate Hamiltonian theory that employs a renormalized linear response theory for the nonequilibrium distribution function of the solvent in the time-varying field of the solute. The theory has been applied to number of simpler systems and checked with molecular dynamics simulations. In the next phase of the research, particular emphasis will be placed on electron transfer reactions and bond-breaking / bond-forming reactions. The surrogate Hamiltonian theory will be extended to include higher order effects such as multiple moments, solute excluded volume and hydrogen bonding effects. They also plan to develop a molecular interpretation for the parameters used by physical organic chemists to quantify nucleophilic solvent assistance in the solvolysis of aliphatic halides in solution. The aim of this research project is to improve the way in which measurable properties of solutions are interpreted in terms of the interactions among the molecular constituents. This is particularly challenging for ionic solutions since the long range of the forces between the ionic charges strongly affect both the measurable properties and the mathematical tools needed to relate them to the molecular models. The work of Friedman and Raineri should provide fundamental molecular insight into the mechanism and dynamics of solvation.