Scaling in Molecular Electronic Spectroscopy: Core-Nonpenetrating Rydberg States

分子电子光谱的缩放：核心非穿透里德伯态

• 批准号: 9730852
• 负责人: Robert Field
• 金额: --
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-04-01 至 2002-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9730852&HistoricalAwards=false
• 关键词: Scaling; Molecular; Electronic; Spectroscopy; Core

The Experimental Physical Chemistry Program supports Prof. Robert W. Field of Massachusetts Institute of Technology in his continuing investigation of `scaling laws,` a priori known functions of quantum numbers. Such scaling laws arise when the coupling between parts of a molecule becomes sufficiently weak. For example, many properties of hydrogenic eigenstates can be expressed as simple functions of Z, n and l. Many atom-based scaling relationships remain useful and instructive, even for polyatomic molecules; for core-nonpenetrating molecular Rydberg states, in which the coupling between Rydberg electron and the molecular ion-core is very weak, the resemblance to hydrogenic systems is quite strong. Field will undertake various types of experiments involving either resonance-enhanced multiphoton ionization or multiple resonance spectroscopies in an effort to develop experimental methods for spectroscopic studies of core-nonpenetrating molecular Rydberg states. These studies will yield information on the electric anisotropies and polarizabilities of molecular ion cores. A few comments about the practical significance of these experiments are warranted. Why should we care about the electric multipole moments of cations? All +1 cations have the same monopole, so this dominant aspect of the interaction of the cation with the outside world is independent of the molecule. Ion-specific long-range interactions, on the other hand, derive from the higher multipoles (and their normal coordinate displacement derivatives). These multipoles and derivatives control the mechanisms and rates of resonant long-range ion-molecule, ion-electron, and possibly ion-surface energy and angular momentum exchange. The information obtainable from systematic studies of core-nonpenetrating Rydberg states would yield valuable insights into a wide variety of processes occurring in plasmas.

实验物理化学项目支持麻省理工学院的罗伯特·W·菲尔德教授继续研究“标度定律”，即量子数的先验已知函数。当分子各部分之间的耦合变得足够弱时，就会出现这种比例定律。例如，氢本征态的许多性质可以表示为 Z、n 和 l 的简单函数。许多基于原子的标度关系仍然有用且具有指导意义，即使对于多原子分子也是如此。对于非穿透核的分子里德伯态，其中里德伯电子与分子离子核之间的耦合非常弱，与氢系统的相似性非常强。 菲尔德将进行各种类型的实验，涉及共振增强多光子电离或多共振光谱学，以努力开发用于核心非穿透分子​​里德伯态光谱研究的实验方法。 这些研究将产生有关分子离子核的电各向异性和极化率的信息。 关于这些实验的实际意义的一些评论是有必要的。 为什么我们应该关心阳离子的电多极矩？ 所有+1阳离子都具有相同的单极子，因此阳离子与外界相互作用的主导方面与分子无关。 另一方面，离子特异性长程相互作用源自更高的多极（及其法向坐标位移导数）。 这些多极子和导数控制共振长程离子-分子、离子-电子以及可能的离子-表面能量和角动量交换的机制和速率。 从对核心非穿透里德伯态的系统研究中获得的信息将为等离子体中发生的各种过程提供有价值的见解。