Computational Aspects of Potential Energy Surfaces

在物理化学计划的这个项目中，McIver将 制定旨在有效评估 玻恩-奥本海默势能面 结果将 用于计算多原子速率常数，包括 隧道效应，对于一些反应， 用变分过渡态的自由基和双自由基 理论 这种计算的关键瓶颈是评估 反应路径哈密顿量的基础几乎所有 目前使用的多原子速率理论。 三条攻击线 在这一瓶颈将追求：发展一种形式主义 它明确地将反应路径哈密顿量 坐标（反应路径和横向振动）和 耦合常数与势能导数;发展 加速计算势能的技术 使用自洽场波函数的能量表面;以及 在分布式存储器上并行实现这些方法 电脑 计算机代码将在以下方面的帮助下开发： 符号代数软件和并行计算机模拟器， 这两种方法都在适当配置的工作站上操作。

In this project in the Physical Chemistry Program, McIver will develop methods aimed at efficiently evaluating Born-Oppenheimer potential energy surfaces. The results will be used in computing polyatomic rate constants, including tunnelling effects, for a number of reactions involving radicals and biradicals using Variational Transition State Theory. The critical bottleneck in such calculations is the evaluation of the Reaction Path Hamiltonian which underlies virtually all currently used polyatomic rate theories. Three lines of attack on this bottleneck will be pursued: development of a formalism which explicitly relates the Reaction Path Hamiltonian coordinates (the reaction path and transverse vibration) and coupling constants to potential energy derivatives; development of techniques for speeding up the calculation of potential energy surfaces using self consistent field wavefunctions; and implementation of the methods on a distributed memory parallel computer. The computer codes will be developed with the aid of symbolic algebra software and a parallel computer simulator, both of which operate on a modestly configured workstation.