Grant for Exploratory Research: Monte Carlo-Gaussian Importance Sampling Evaluation of Real-Time Feynman Path Integrals

化学系的理论与计算化学项目正在支持爱荷华州立大学David Hoffman教授关于量子动力学计算新方法的研究。这是与休斯顿大学的Donald Kouri教授的一个合作项目，他的努力也得到该司的支持。费曼路径积分法用于取代矩阵积、特征值和逆的计算，这些计算随着系统规模的增加而迅速增加。高斯重要抽样是用来产生一个可控的方差在蒙特卡洛积分。目标是使比以前更大尺寸的散射系统的完全量子力学处理成为可能。在过去，用于分析化学反应的精确数值量子力学方法仅限于包含不超过三个原子的系统，其中至少有一个必须是氢。该项目正在测试一种新的计算技术，该技术有望在更大的系统上进行此类计算，更广泛地说，可以用于研究其他量子力学碰撞过程。

The Theoretical and Computational Chemistry Program in the Chemistry Division is supporting research by Prof. David Hoffman at Iowa State University on a new approach to quantum dynamics calculations. This is a collaborative project with Professor Donald Kouri of the University of Houston whose effort is also being supported by the Division. The Feynman path integral method is used to replace the customary calculation of matrix products, eigenvalues, and inverses which scale very rapidly with system size. Gaussian importance sampling is used to produce a manageable variance in the Monte Carlo integral. The goal is to make possible fully quantum mechanical treatment of scattering systems of a larger size than previously possible. %%% Numerically exact quantum mechanical methods for analyzing chemical reactions have in the past been limited to systems containing no more than three atoms, at least one of which must be hydrogen. This project is testing a new computational technique which offers promise of permitting such calculations on larger systems and, more generally, can be used in studying other quantum mechanical collisional processes.