Quantum Operator Approaches to Condensed Phase and Multidimensional Reaction Dynamics

叶史瓦大学的史蒂文·施瓦茨得到了理论和计算化学项目的资助，继续他在凝聚相多维反应动力学的量子算子方法方面的研究。 Schwartz对溶液中系统的量子动力学的解的方法是基于使用微观哈密顿系统的广义朗之万方程，其中离散谐波浴双线性耦合到系统坐标。 使用演化算子扩展和再确认方法，施瓦茨将这种方法应用于溶剂化化学体系中反应坐标的研究。 除了将方法扩展到涉及量子激活速率理论的多维系统中的量子模拟之外，Schwartz还将他的操作员方法应用于以下化学感兴趣的系统：1）质子在非质子极性溶剂中从苯酚转移到胺; 2）溶解在水中的甘氨酸中的内部质子转移;和3）醇脱氢酶反应中的氢化物转移。 具体问题包括空间相关摩擦的影响、浴的温度依赖性以及促进振动的重要性。在由相对较少原子组成的系统的气相化学反应的理论处理方面已经取得了很大进展。使用最先进的理论方法，现在可以解释这种系统的大量实验细节。然而，化学家感兴趣的绝大多数反应都发生在溶剂存在下的凝聚相体系中。处理这种复杂系统的理论模型还处于发展的早期阶段。施瓦茨正在开发新的理论方法来处理溶剂化化学系统进行化学反应，量子效应可能是重要的。

Steven Schwartz of Yeshiva University is supported by a grant from the Theoretical and Computational Chemistry Program to continue his research in quantum operator approaches to condensed phase multidimensional reaction dynamics. Schwartz' approach to the solution of the quantum dynamics of a system in solution is based on a Generalized Langevin Equation using a microscopic Hamiltonian system in which a discrete harmonic bath is bilinearly coupled to a system coordinate. Using an evolution operator expansion and resummation methodologies, Schwartz applies this methodology to the study of reaction coordinates in solvated chemical systems. In addition to extending the methodology to quantum simulations in many dimensional systems involving quantum activated rate theory, Schwartz will apply his operator approach to the following systems of chemical interest: 1) proton transfer from phenol to amine in aprotic, polar solvents; 2) internal proton transfer in glycine dissolved in water; and 3) hydride transfer in alcohol dehydrogenase reaction. Specific questions to be examined include the effect of spatially dependent friction, the temperature dependence of the bath, and the importance of promoting vibrations.A great deal of progress has been made in the theoretical treatment of gas phase chemical reactions of systems consisting of relatively few atoms. Using state-of-the-art theoretical methods, it is now possible to explain a great deal of the experimental detail for such systems. However, the large majority of reactions which are of interest to chemists occur in condensed phase systems in the presence of solvent. The theoretical models for treating such complex systems are in a much earlier stage of development. Schwartz is developing new theoretical approaches for dealing with solvated chemical systems undergoing chemical reactions where quantum effects may be important.