Spectroscopy and Dynamics of Ions

Lineberger提出了一项更新建议，利用负离子光电子能谱和离子配合物的超快泵探针激发来研究负离子及其团簇在气相中的性质。利用这些技术，结构信息和反应动力学将被用于研究一类广泛的系统，这些系统要么是化学瞬态，要么是反应中间体，要么是过渡态物种。要研究的分子包括有机自由基和双自由基，金属和金属团簇，以及单分子和双分子过程的过渡态。电子亲和，单重态-三重态分裂，振动频率和几何信息将得到。用立体化学方法合成了苯（C6H4）的邻位、间位和对构象。用超快方法研究的单分子过程包括偏乙炔中的1,2氢位移生成乙炔。离子在溶剂笼中的动力学也将通过跟踪笼分解产物的外观以及部分溶剂化离子中电子转移后的溶剂重组来扩展。这些研究的目标之一是增加对驱动最简单化学转化过程的定量理解。通过研究被分离的和被溶剂包围的分子的化学转化，林因伯格将能够证明不同的溶剂对反应性的影响以及对这些反应进行的速率的影响。

Lineberger has submitted a renewal proposal to investigate the properties of negative ions and their clusters in the gas phase using negative ion photoelectron spectroscopy and ultrafast pump-probe excitation of ionic complexes. With these techniques both the structural information and the reaction dynamics will be investigated for a broad class of systems which are either chemical transients, reactive intermediates, or transition state species. Among the molecules to be studied are organic radicals and biradicals, metals and metal clusters, and transition states for both unimolecular and bimolecular processes. Electron affinities, singlet-triplet splittings, vibrational frequencies, and geometrical information will be obtained. Ortho, meta, and para forms of benzyne (C6H4) will be synthesized using stereochemical control. Unimolecular processes investigated by ultrafast methods include the 1,2 hydrogen shift in vinylidene to form acetylene. The dynamics of ions in a solvent cage will also be extended by following the appearance of products of cage disintegration as well as solvent reorganization following electron transfer in partially solvated ions. One goal of these studies is to increase the quantitative understanding of the processes driving the simplest chemical transformations. By studying the chemical transformations of molecules which are both isolated as well as surrounded by solvent species, Lineberger will be able to demonstrate the effect that different solvents have on reactivity as well as on the rates at which these reactions proceed.