The Incorporation of Quantum Effects in the Simulation of Proton Transfer Reactions

理论和计算化学计划支持 教授Hammes-Schiffer在圣母大学作为职业生涯的一部分 青年科学家计划。本研究的目的是 开发和应用新的方法来模拟动态过程 涉及多个质子转移反应。 为了模拟 质子转移反应，将量子 被转移的氢原子的机械行为必须 开发 在表面跳跃方法中，例如分子动力学， 量子跃迁（MDQT），轨迹分裂成分支， 每一个都被分配到一个特定的质子量子态， 过程（即涉及多个通道或途径的过程）是 准确描述。 MDQT直接扩展到流程 然而，涉及多个质子转移步骤， 可行 所提出的新方法MC-MDQT将MDQT与 多组态（MC）自洽场方法，并将描述分支过程 适当地以及允许量子力学处理多个氢 原子的 这种方法将适用于两类系统。 一是 质子沿着氢键水分子的线性链沿着传输。 这是一个重要的过程，因为质子的快速传输， 在生物学上重要的系统中， 细菌视紫红质和光合反应中心被认为是发生 沿着这样的链条。 将研究的第二类系统是 在酶如乙醇脱氢酶中的氢转移， 在糖酵解中的重要作用。 动力学同位素效应实验表明 氢隧道效应在很多酶反应中都很重要。 这些应用程序的目标是阐明潜在的物理 质子转移反应的原理，并阐明详细的 这些重要的生物反应的机制。 教育 卡雷尔这笔赠款的目标是促进计算机的更广泛使用 有机化学和生物化学领域的模拟。 一门课程 已经设计好了。 这一点的结果是， 项目是一个计算机实验室工作簿的创建，以及教科书 这将有助于在其他地方开发此类课程， 高校 一般的质子转移反应涉及氢的通过， 原子核从供体到受体。 实验表明 氢原子可以隧穿通过这样做所需的能量势垒 一种反应 这项研究将集中在将量子 机械行为，如隧道效应，以模拟质子 转移反应 该Carreer助学金的教育目标是 促进在有机领域更广泛地使用计算机模拟， 化学和生物化学。 一门计算机模拟课程已经 被设计。 本课程由三部分组成：讲座传达 计算机模拟的基本概念;计算机实验室提供 在分子建模方面的实践经验，而独立研究 激励学生追求未来的项目。 这一点的结果是， 项目是一个计算机实验室工作簿的创建，以及教科书 这将有助于在其他地方开发此类课程， 高校

The Theoretical and Computational Chemistry program is supporting Professor Hammes-Schiffer at the University of Notre Dame as part of the CAREER program for young scientists. The objective of this research is to develop and apply new methods for simulating dynamical processes involving multiple proton transfer reactions. In order to simulate proton transfer reactions, methods that incorporate the quantum mechanical behavior of the hydrogen atoms being transferred must be developed. In surface-hopping methods such as molecular dynamics with quantum transitions (MDQT), trajectories split into branches that are each assigned to a particular proton quantum state, so branching processes (i.e. processes involving multiple channels or pathways) are described accurately. The direct extension of MDQT to processes involving multiple proton transfer steps, however, is not computationally feasible. The proposed new method, MC-MDQT, combines MDQT with a multiconfigurational (MC) self-consistent-field approach and will describe branching processes properly as well as allow the quantum mechanical treatment of multiple hydrogen atoms. This method will be applied to two classes of systems. The first is proton transport along linear chains of hydrogen-bonded water molecules. This is an important process because the rapid transport of protons over large distances in biologically important systems such as bacteriorhodopsin and photosynthetic reaction centers is thought to occur along such chains. The second class of systems that will be studied is hydrogen transfer in enzymes such as alcohol dehydrogenase, which plays a vital role in glycolysis. Kinetic isotope effect experiments indicate that hydrogen tunneling is significant in a variety of enzyme reactions. The goal of these applications is to elucidate the underlying physical principles of proton transfer reactions and to clarify the detailed mechanisms of these biologically important reactions. The educational objectives of this Carreer grant are to promote the wider use of computer simulations in the areas of organic chemistry and biochemistry. A course in computer simulations has already been designed. An outgrowth of this project is the creation of a computer lab workbook, as well as a textbook which will facilitate the development of such courses at other universities. A general proton transfer reaction involves the passing of a hydrogen atom nucleus from a donor to an acceptor. Experiments have shown that the hydrogen atom can tunnel through an energy barrier required for such a reaction. This research will focus on methods that incorporate quantum mechanical behavior, such as tunneling in order to simulate proton transfer reactions. The educational objectives of this Carreer grant are to promote the wider use of computer simulations in the areas of organic chemistry and biochemistry. A course in computer simulations has already been designed. The course consists of three parts: The lectures convey the fundamental concepts for computer simulation; Computer labs provide hands on experience with molecular modeling, while independent research motivates sutdents to pursue future projects. An outgrowth of this project is the creation of a computer lab workbook, as well as a textbook which will facilitate the development of such courses at other universities.