Laser spectroscopy of transient molecules/IVR mediated torsion

这里提出的研究的一部分是关于不稳定分子的电和磁性质的表征。这些分子具有很强的活性，因此能存活的时间很短，一毫秒或更短。由于不稳定分子充当反应的中间体，它们参与了物理、化学、天体化学和其他科学分支的各种过程。这些分子相关性的例子是监测大气中的污染物，臭氧消耗的本质，监测半导体器件的制造，了解燃烧和其他烟灰形成过程，以及行星和恒星大气的演变。研究的另一部分关注的问题是，当能量迅速沉积到分子的一种振动模式中时，会发生什么。这是理解孤立分子如何将能量重新分配到多个自由度的关键问题。这在需要控制化学反应的化学动力学和激光化学中具有重要意义。为了找到这个问题的答案，我们需要更多地了解分子中不同的振动是如何相互作用的。事实证明，如果分子具有一种或多种易于激活的振动模式，它可以比没有这种模式的分子更容易地分配从外部源接收到的能量。这种分子的例子是乙烷（CH3CH3）和CH3SiH3。乙烷中的两个甲基可以在C-C键上沿相反方向旋转。与C-H模式相比，这种模式需要相对较少的能量来激活。

One part of the research proposed here is concerned with the characterization of the electric and magnetic properties of unstable molecules. These molecules are highly reactive and thus live for a very short time, a millisecond or less. Because they act as reaction intermediates, unstable molecules take part in a wide variety of processes in physics, chemistry, astrochemistry, and other branches of science. Examples of the relevance of these molecules are the monitoring of pollutant in our atmosphere, the nature of ozone depletion, monitoring of the manufacturing of semiconductor devices, understanding combustion and other soot forming processes, and the evolution of the atmospheres of planets and stars. The other part of the research is concerned with the question of what happens when energy is rapidly deposited into one of the vibrational modes of a molecule. This is a key question to understanding how an isolated molecule redistributes its energy into its many degrees of freedom. This has important implications in chemical dynamics and laser chemistry where it is desirable to control chemical reactions. To find answers to this problem, we need to learn more about how different vibrations in a molecule interact. It turns out that if the molecule possesses one or more vibrational modes that are easily activated it can distribute the energy it receives from the outside sources much more easily than a molecule with no such modes. Examples of such molecules are ethane (CH3CH3) and CH3SiH3. The two methyl groups in ethane can rotate in opposite directions about the C-C bond. This mode requires a relatively small amount of energy to be activated as compared to for example the C-H mode.