Reactions of Highly Excited Molecules: From Supercollisions to Super-reactions?

波士顿大学的Amy Mullin在实验物理化学项目的支持下进行研究，旨在阐明控制气相中高激发多原子分子碰撞和反应过程的行为和基本原理。实验研究将使用脉冲紫外纳秒吸收，然后是快速无辐射衰变，以制备高度振动激发的苯类分子，其内能范围从15,000到45,000波数。高分辨率瞬态红外吸收探测将用于监测碰撞伙伴的能量增益或反应产物的外观。项目计划是：(1)研究受激azulene碰撞弛豫的能量依赖性，(2)发现相对较小的受激分子（如二硫化碳）的内能含量如何影响碰撞猝灭动力学，(3)通过测量氨中的能量增益来探索静电相互作用如何影响高能分子的碰撞弛豫。(4)研究了内能在高能分子吸氢和吸氘反应中的作用；(5)确定了水中和氘水浴中高能分子交换反应与碰撞能量传递的竞争方式；(6)进行了经典轨迹计算，以帮助解释实验结果。活化分子几乎在化学和生物化学的各个层面上都起着重要的作用。含有大量能量的分子通常是最活跃的物质，因此对于确定热环境的化学性质是最重要的。这种情况对于涉及大气、等离子体和燃烧化学的高温过程尤其如此。在这项研究中获得的基本见解可能会导致这些领域更清洁，更有效和更安全的应用。在研究生教育的同时，该项目为本科生和高中生提供了直接参与最先进科学研究的重要机会。

Amy Mullin of Boston University is supported by the Experimental Physical Chemistry Program to carry out studies aimed at elucidating the behavior and underlying principles that govern collisional and reactive processes of highly excited polyatomic molecules in the gas phase. Experimental studies will use pulsed UV nanosecond absorption, followed by rapid radiationless decay, to prepare highly vibrationally excited benzene-like molecules with internal energies ranging from 15,000 to 45,000 wavenumbers. High-resolution transient infrared absorption probing will be employed to monitor energy gain in collision partners or the appearance of reaction products. Project plans are to (1) investigate the energy dependence of collisional relaxation in excited azulene, (2) discover how internal energy content in relatively small excited molecules such as carbon disulfide influences collisional quenching dynamics, (3) explore how electrostatic interactions influence collisional relaxation of high-energy molecules by measuring energy gain in ammonia, (4) investigate the role of internal energy on hydrogen and deuterium abstraction reactions of high-energy molecules, (5) determine the ways in which exchange reactions of high-energy molecules compete with collisional energy transfer in water and deuterated water baths, and (6) perform classical trajectory calculations to aid in interpreting the experimental findings. Activated molecules play important roles in chemistry and biochemistry at almost every level. Molecules containing large amounts of energy are usually the most reactive species and hence are among the most important for determining the chemistry of thermal environments. This situation is especially true for high temperature processes involved in atmospheric, plasma, and combustion chemistry. The fundamental insights to be gained in this research may lead to cleaner, more efficient, and safer applications in these areas. Along with the education of graduate students, this project gives undergraduates and high school students important opportunities to participate directly in the state-of-the-art scientific research.