Theoretical Studies of Organic Reactions in Solution

William Jorgensen教授获得了理论与计算化学项目的资助，他将量子力学、统计力学和分子动力学模拟相结合，对气相和溶液中的有机化学反应进行理论研究。这一理论研究的结果在基本分子水平上对化学反应性的理解提供了重要的解释。Jorgensen采用从头算分子轨道计算来提供气相反应的能量表面和描述溶质-溶剂相互作用的势函数。然后通过计算溶液中的自由能面来确定溶剂化的效果。这包括蒙特卡罗或分子动力学模拟反应系统加上大约300个溶剂分子在一个周期细胞。最后，通过在过渡态区域开始的轨迹计算来研究反应动力学。这些计算提供了关于关键问题的详细信息，包括气相和溶液中的反应机制，中间体的存在，溶剂诱导活化屏障的来源，沿着反应路径的溶剂化变化，反应过程中的能量重新分配，以及溶剂在决定反应动力学中的动态作用。

Professor William Jorgensen is supported by a grant from the Theoretical and Computational Chemistry Program to perform theoretical studies of organic chemical reactions both in the gas phase and in solution using a combination of quantum mechanics, statistical mechanics and molecular dynamics simulations. The results of this theoretical research provide an important interpretation of chemical reactivity at the fundamental molecular level of understanding. Jorgensen employs ab initio molecular orbital calculations to provide energy surfaces for reactions in the gas phase and potential functions that describe solute-solvent interactions. The effect of solvation is then determined by computing the free energy surfaces in solution. This involves Monte Carlo or molecular dynamics simulations for the reacting systems plus about 300 solvent molecules in a periodic cell. Finally, the reaction dynamics are studied by trajectory calculations that are started in the transition state regions. These computations provide detailed information on key issues including the reaction mechanisms in the gas phase and in solution, the existence of intermediates, the origin of solvent induced activation barriers, changes in solvation along reaction paths, energy redistribution during reactions, and the dynamic role of the solvent in determining reaction kinetics.