Ab Initio Calculation of Accurate Molecular Wave Functions

本项目旨在开发分子电子学中基于孪晶的方法 结构理论由NSF理论和 计算化学程序与高级科学计算 师. 方法将被开发用于计算准确的，ab 第一性原理，小分子，电子波函数 高斯孪生（Gaussian geminals） 显式相关、两粒子、高斯基函数）。 偕 分子参数将从优化的原子中提取 波函数 将开发可扩展的算法以供实施 在并行计算机上。 量子力学电子波函数是一个数学函数 原子中所有电子的空间和自旋坐标， 分子。 这些多体功能传统上表达在 轨道项，即单个轨道坐标的函数 电子。轨道为基础的概念和计算方法发挥了 现代化学理论的核心作用，但有一个实际的限制， 使用现有的基于轨道的计算所能达到的精度 超级计算机 该项目的目标是开发改进的 计算方法使用geminals（显式函数的 一对电子的坐标）而不是轨道。 如果成功， 这将大大提高理论预测的准确性 气相反应速率，如改进计算机所需的速率， 地球大气层的模型

This project to develop geminal-based methods in molecular electronic structure theory is supported jointly by the NSF Theoretical and Computational Chemistry Program and the the Advanced Scientific Computing Division. Methods will be developed for the computation of accurate, ab initio, small molecule, electronic wavefunctions using contracted Gaussian geminals (predetermined linear combinations of explicitly-correlated, two-particle, Gaussian basis functions). Geminal parameters for molecules will be extracted from optimized atomic wavefunctions. Scalable algorithms will be developed for implementation on parallel computers. The quantum mechanical electronic wavefunction is a mathematical function of the spatial and spin coordinates of all the electrons in the atom or molecule. These many-body functions are traditionally expressed in terms of orbitals, i.e. functions of the coordinates of a single electron. Orbital-based concepts and computational methods play a central role in modern chemical theory, but there is a practical limit to the accuracy attainable in orbital-based computations using existing supercomputers. The goal of this project is to develop improved computational methods using geminals (explicit functions of the coordinates of a pair of electrons) rather than orbitals. If successful, this will significantly increase the accuracy of theoretical predictions of gas phase reaction rates such as those required for improved computer models of the earth's atmosphere.