Optical Absorption Spectroscopy of Metal Containing Molecules

本研究由化学学部实验物理化学项目资助。在三个相关的任务中，Steimle将：a)使用瞬态调频（TFM）光谱检测和表征过渡金属氧化物；b)用激光诱导荧光光谱检测和表征被认为是火焰抑制催化中间体的含铁分子；c)执行塞曼和斯塔克光谱来表征三维过渡金属氧化物和单氮化物。利用现有的激光烧蚀/超音速膨胀源或直流放电/超音速膨胀源产生含金属自由基。分子种类将通过分析它们的电子光谱以及光学斯塔克和塞曼光谱分裂来表征。了解过渡金属的氧化反应不仅在化学中具有重要的基础意义，而且对表面科学和冶金学等许多相关领域都至关重要。某些含铁化合物已被发现在抑制火焰方面比含卤素化合物更有效，对环境更友好，而含卤素化合物的使用正在逐步淘汰。所提出的研究将对理解这些主题作出重要贡献。虽然实验和结果分析是复杂而精密的，但它们适合在首席研究员的监督下工作的研究生和本科生的参与

This research is funded by the Experimental Physical Chemistry Program of the Chemistry Division. In three related tasks Steimle will: a) detect and characterize transition metal dioxides using transient frequency modulation (TFM) spectroscopy; b) detect and characterize by laser induced fluorescence spectroscopy Fe-containing molecules thought to be catalytic intermediates in flame suppression; and c) perform Zeeman and Stark spectroscopy to characterize 3d transition metal monoxides and mononitrides. The metal-containing radicals will be generated using either an existing laser ablation/supersonic expansion source or a dc-discharge/supersonic expansion source. The molecular species will be characterized through the analysis of their electronic spectra as well as of the optical Stark and Zeeman spectral splittings. Understanding the oxidation reaction of transition metals is both of fundamental importance in chemistry and is crucial to many related areas such as surface science and metallurgy. Certain Fe-containing compounds have been found to be substantially more effective at flame inhibition and are environmentally friendlier than halogen-containing compounds, whose use is being phased out. The proposed research will make important contributions to the understanding of these topics. Although the experiments and the analyses of the results are complex and sophisticated, they lend themselves to the involvement by graduate and undergraduate students who work under the supervision of the principal investigator