Competitive Reaction Pathways

实验物理化学项目支持南加州大学的 Curt Wittig 继续研究光诱导反应。 他将重点关注两组实验：（a）二聚体受限几何形状中的反应和（b）阈值下的单分子反应速率。 在前者中，他将使用双共振技术来选择簇大小。 将选择簇的旋转分辨状态并询问它们的光化学性质。 Wittig 将研究 HF-HCl、HCl-HF 和 HCl 二聚体及其氘代类似物中的氢交换反应和非弹性散射。 第二组研究将重点关注二氧化氮、HNCO、水和 HF。 这些研究的一个基本主题是通过提供基准数据来挑战理论模型。 因此，在某些情况下，需要重新考虑相关气相过程的现有模型。 在其他情况下，研究的系统的动力学被认为是已知的相关气相过程。 此处要进行的簇实验将显示由于受限入口通道而产生的效应，即由于簇的几何形状而产生的效应。 此类工作开始以高精度弥合气相和凝聚相之间的差距，同样是通过实验基准，尽管是在既不是凝聚相也不是气相的微观世界中。 因此，这些研究的结果将对增进我们对反应动力学的知识和理解产生非常重大的影响。

The Experimental Physical Chemistry Program supports Curt Wittig of the University of Southern California in his continuing studies of photoinduced reactions. He will focus on two sets of experiments: (a) reactions in the restricted geometries of dimers and (b) unimolecular reaction rates at threshold. In the former, he will use double resonance techniques for cluster size selection. Rotationally resolved states of clusters will be selected and their photochemistries interrogated. Wittig will study the hydrogen exchange reaction and inelastic scattering in HF-HCl, HCl-HF and HCl dimer and its deuterated analogs. The second set of studies will focus on nitrogen dioxide, HNCO, water and HF. An underlying theme of these studies is to challenge theoretical modeling by providing benchmark data. Thus, in some cases, existing models of the associated gas phase phase processes will need to be reconsidered. In other cases, systems are studied for which the dynamics are believed to be known for the associated gas phase processes. The cluster experiments to be carried out here will then display effects attributable to the restricted entrance channel, i.e., effects due to the geometry of the cluster. Such work starts to bridge the gap between the gaseous and condensed phases at a high level of precision, again with experimental benchmarks, albeit in a microcosm that is neither the condensed nor gas phase. Results from these investigations will thus have a very significant impact in advancing our knowledge and understanding in reaction dynamics.