International Collaboration in Chemistry: Quantum Dynamics of 4-Atom Bimolecular Reactions

国际化学合作：4 原子双分子反应的量子动力学

• 批准号: 1025960
• 负责人: Richard Zare
• 金额: $ 38万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-15 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1025960&HistoricalAwards=false
• 关键词: International; Collaboration; Chemistry; Quantum; Dynamics

Richard Zare of Stanford University is supported by an International Collaborations in Chemistry (ICC) award from the Chemical Structure and Mechanisms program in the Chemistry division to carry out detailed studies of the quantum dynamics of four-atom bimolecular reaction, in collaboration with Stuart Althorpe of Cambridge University in the UK. The proposed research builds on a recent series of collaborations between Zare's experimental research group and the theoretical group of S.C. Althorpe in which they studied the simplest chemical reaction (H + H2 - H2 + H and isotopic variants) at an unprecedented level of detail and rigor, both experimentally and theoretically, using time-dependent wave packets to interpret the experimental scattering data. Surprisingly, this research has revealed a variety of unusual mechanistic effects that result from the quantum properties of the hydrogen nuclei, and which have implications for a wide range of other chemical reactions. The current project extends these studies to one of the simplest four-atom reactions: H + H2O - H2 + OH. The significance of the extra atom is that it allows for a variety of effects that a three-atom reaction such as H + H2 is obviously too simple to capture, such as stereodynamical processes, and the effect of mode-selectivity on the wave function at the transition state. The theoretical part of this collaboration extends to four atoms the "plane wave packet method" of Althorpe and co-workers, in which the scattering into space of the products of a reaction is described by time-evolving wave packets which can be mapped directly onto experimentally measured state-to-state differential cross sections. The cross sections are measured by the Zare group, using an extension of a newly constructed instrument for imaging the three-dimensional velocity distribution of photo-ionized products from photo-initiated chemical reactions. An important feature of this research is that both highly accurate theory and novel and challenging experimental techniques are required; it is truly cutting edge research. This fundamental research, like the prior work on the simplest three atom reaction, is expected to lead to surprising results that will influence our perceptions of reaction mechanisms and reaction dynamics. The work gives a deeper understanding of the role that quantum mechanics plays in many reactive processes. The work is also likely to find its way into textbooks on physical chemistry, and influence how students and their teachers think about chemical reaction dynamics. Several graduate students, in the US and the UK are being trained in the leading-edge theoretical and experimental techniques as part on an international collaboration in which there is a high level of synergy between theory and experiment.

斯坦福大学的Richard Zare获得化学系化学结构和机制项目的国际化学合作奖（ICC）的支持，与英国剑桥大学的Stuart Althorpe合作，对四原子双分子反应的量子动力学进行详细研究。拟议的研究建立在Zare的实验研究小组和S.C.的理论小组之间最近的一系列合作基础上。在Althorpe的研究中，他们以前所未有的细节和严格程度研究了最简单的化学反应（H + H2 - H2 + H和同位素变体），无论是实验还是理论，都使用时间相关的波包来解释实验散射数据。令人惊讶的是，这项研究揭示了各种不寻常的机械效应，这些效应是由氢原子核的量子特性引起的，并且对许多其他化学反应都有影响。 目前的项目将这些研究扩展到最简单的四原子反应之一：H + H2O-H2 + OH。额外原子的重要性在于它允许各种效应，例如立体动力学过程，以及模式选择性对过渡态波函数的影响，而三原子反应（如H + H2）显然太简单而无法捕获。 这项合作的理论部分扩展到四个原子的“平面波包方法”的奥尔索普和同事，其中散射到空间的反应产物是由时间演变的波包，可以直接映射到实验测量的状态到状态微分截面描述。 的横截面测量的Zare组，使用一个扩展的新建成的仪器成像的三维速度分布的光致电离产物从光引发的化学反应。 这项研究的一个重要特点是，既需要高度准确的理论，又需要新颖而具有挑战性的实验技术;这是真正的前沿研究。这项基础研究，就像之前对最简单的三原子反应的研究一样，预计将导致令人惊讶的结果，这些结果将影响我们对反应机制和反应动力学的看法。这项工作使人们对量子力学在许多反应过程中所起的作用有了更深入的理解。 这项工作也可能会进入物理化学教科书，并影响学生和老师对化学反应动力学的看法。 美国和英国的几名研究生正在接受前沿理论和实验技术的培训，这是国际合作的一部分，理论和实验之间存在高度的协同作用。