Quantum-State-Selected Ion-Molecule Reaction Dynamics: Effects of Translational, Rotational, Vibrational, Spin-Orbit, and Electronic States on Chemical Reactivity

在这个由化学系化学结构动力学和机理(CSDM-A)计划资助的项目中，加州大学戴维斯分校的吴卓耀教授正在使用他实验室以前开发的仪器来探索化学反应如何依赖于反应分子中包含的能量。分子根据其不同的运动模式拥有能量，例如，它们如何在空间中移动(平移)，它们如何振动，以及它们如何旋转。分子能也包括分子内电子的能量。吴教授开发了一种新的仪器，可以产生具有精确已知的平移、振动、转动和电子能量的分子离子(带负电荷或正电荷的分子，例如H2O或O2)。这些“状态选择”的分子离子然后与其他中性分子反应，然后反应产物提供了不同类型的分子能量如何影响它们的反应性的洞察。吴教授的研究可能使有朝一日基于分子内的能量分布来控制化学反应成为可能。该项目涉及最先进的真空紫外线(VUV)激光光源和新的激光光谱技术的开发。因此，该项目为培训下一代激光光谱学和动力学研究人员提供了一个极好的教育机会。目前实验的重点是对各种离子-分子反应进行绝对积分截面测量，这些反应涉及量子振荡态选择的离子，如N_2、H_2O、H_2和O_2。由于最近在制备长寿命V(A5DJ)、V(A5FJ)和V(A3FJ)自旋轨道和电子态的钒正离子方面取得了成功，Ng教授的团队还计划检查钒离子反应的量子态选择测量。本研究中要包括的中性反应物是Ne、Ar、H2、HD、D2、O2、N2、CO、NO、HCN、H2O、D2O、CH4、C2H2、C2H4、C2H6、C3H4、C4H2、C6H6、CH3OH和NH3。这些离子-分子反应在过渡金属阳离子络合物的催化功能和理解行星大气中发生的化学作用方面发挥着关键作用。所获得的结果也将作为最先进的量子动力学计算的基准。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

In this project funded by the Chemical Structure Dynamics and Mechanism (CSDM-A) program of the Chemistry Division, Professor Cheuk-Yiu Ng of the University of California at Davis is using instruments previously developed in his laboratory to explore how chemical reactions depend on how energy is contained in the reacting molecules. Molecules possess energy according their different modes of motion, for example how they move through space (translational), how they vibrate, and how they rotate. Molecular energy also includes the energy of the electrons within the molecules. Prof. Ng has developed a novel instrument that can produce molecular ions (molecules with negative or positive charge, for example H2O+ or O2+) with precisely known translational, vibrational, rotational, and electronic energies. These "state selected" molecular ions are then reacted with other neutral molecules, and the reaction products then provide insight into how the different types of molecular energy influences their reactivity. Prof. Ng's research may make it possible one day to control chemical reactions based on the distribution of energy within the molecules. This project involves the development of state-of-the-art vacuum ultraviolet (VUV) laser sources and novel laser spectroscopic techniques. As such, the project is providing an excellent education opportunity for training the next generation of researchers in laser spectroscopy and dynamics. The current focus of the experiment is to perform absolute integral cross section measurements for a variety of ion-molecule reactions involving quantum-rovibronic-state-selected ions such as N2+, H2O+, H2+, and O2+. Due to the recent success in preparing vanadium cation in long-lived V+ (a5DJ), V+ (a5FJ), and V+ (a3FJ) spin-orbit and electronic states, Prof. Ng's group also plans to examine quantum-state-selected measurements for the reactions of vanadium ions. The neutral reactants to be included in this study are Ne, Ar, H2, HD, D2, O2, N2, CO, NO, HCN, H2O, D2O, CH4, C2H2, C2H4, C2H6, C3H4, C4H2, C6H6, CH3OH, and NH3. These ion-molecule reactions play a pivotal role in the catalytic function of transition-metal cations complexes and the understanding of the chemistry occurring in planetary atmospheres. The results obtained would also serve as benchmarks for state-of-the-art quantum dynamics calculations.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.