Vibrational Spectroscopy of Ion Solvent Clusters

离子溶剂簇的振动光谱

• 批准号: 9700610
• 负责人: Mitchio Okumura
• 金额: $ 35.71万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 2001-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9700610&HistoricalAwards=false
• 关键词: Vibrational; Spectroscopy; Ion; Solvent; Clusters

The Experimental Physical Chemistry Program supports Mitchio Okumura of California Institute of Technology in his continuing studies on anionic cluster solvation. Specifically, he uses vibrational predissociation spectroscopy to study the structure of various anions hydrated with `n` molecules of water, as a function of n. Apparently, experimental studies on cationic hydrate clusters and anions clustered with rare gases indicate that solvation shells form and the ion is in the interior. Theoretical work on halide anionic hydrate clusters suggest, on the other hand, that the ion is bound to the surface of clustered water molecules, and as the cluster size increases, a transition from surface- to interior-solvation occurs. Okumura will focus on the hydrogen stretching region; the frequency shifts and linewidths in this region should yield insight on hydrogen bonding both between ion and solvent molecules and among solvent molecules. In addition, two photon (infrared-infrared double resonance predissociation or infrared-ultraviolet vibrationally assisted photodetachment) spectroscopy will be brought to bear on those clusters that are more strongly bound. Finally, cluster solvation of acids implicated in stratospheric aerosol chemistry will be investigated. An ab initio theoretical effort will be carried out to aid in determining cluster geometries. While the aim of this work is to investigate ion-solvent interactions at a fundamental level, a second motivation is to elucidate solvation processes and ionic reaction mechanisms of relevance to atmospheric chemistry. Many of the systems that will be investigated play central roles in heterogeneous reactions occuring in the stratosphere and troposphere. Adducts of these ionic hydrates with atmospheric species such as nitric acid and hydrochloric acid may serve as models of intermediates in the adsorption and ionic dissociation on atmospheric aerosols.

实验物理化学计划支持Mitchio Okumura， 加州理工学院在他的继续研究阴离子 团簇溶剂化 具体来说，他使用振动预解离 光谱学，以研究与“n”水合的各种阴离子的结构 水的分子数，作为n的函数。 显然，实验研究 阳离子水化物簇和阴离子稀有气体簇 表明溶剂化壳层形成，离子在内部。 卤化物阴离子水合物簇的理论工作表明，另一方面， 另一方面，离子被束缚在聚集的水分子表面， 随着团簇尺寸的增加，从表面到表面的过渡 发生溶剂化。 Okumura将专注于氢的拉伸 区域;该区域中的频移和线宽应产生 对离子和溶剂分子之间氢键作用的认识， 在溶剂分子中。 此外，双光子（红外-红外 双共振预解离或红外-紫外振动 辅助光剥离）光谱学将对那些 更紧密结合的簇。 最后， 将对平流层气溶胶化学中涉及的酸进行研究。 一个从头开始的理论努力将进行援助， 确定簇的几何形状。 虽然这项工作的目的是研究离子-溶剂相互作用， 第二个动机是阐明溶剂化 与大气有关的过程和离子反应机制 化学. 许多将被调查的系统发挥着核心作用 在平流层发生的多相反应中的作用， 对流层 这些离子水合物与大气物种的加合物 例如硝酸和盐酸可以作为 大气吸附和离子解离中的中间体 气溶胶