X-Ray Atomic and Molecular Spectroscopy: Probing Fundamental Interactions between X-Rays and Matter

X 射线原子和分子光谱：探测 X 射线与物质之间的基本相互作用

• 批准号: 0555699
• 负责人: Dennis Lindle
• 金额: --
• 依托单位: University of Nevada Las Vegas
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-07-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0555699&HistoricalAwards=false
• 关键词: Ray; Atomic; Molecular; Spectroscopy; Probing

This experimental research program is aimed at pursuing fundamental investigations of physical phenomena important to understanding x-ray interactions with atoms and molecules. The primary scientific focus is probing the limits of the dipole approximation, the simplest reasonable treatment of photon interactions, for soft-x-ray photoionization and inelastic x-ray scattering (x-ray emission) from mostly molecular targets. Photoemission studies done as part of this program have demonstrated, in some cases rather unexpectedly, quantitatively large non-dipole effects at surprisingly low photon energies, leading to a minor paradigm shift within the photoemission community regarding the general validity of the dipole approximation. The proposed research will be carried out using three unique home-built instruments, one for gas-phase photoemission using time-of-flight electron-energy analysis, one for high-resolution polarized x-ray emission of gases, and a third for measuring macroscopic currents in gas-phase samples irradiated with beams of x-rays. The broader impact of the program involves student training as well as applications to material science.

该实验研究计划旨在对理解X射线与原子和分子相互作用的重要物理现象进行基础研究。主要的科学焦点是探索偶极近似的极限，这是光子相互作用的最简单合理的处理方法，用于软x射线光电离和大多数分子目标的非弹性x射线散射（x射线发射）。作为该计划的一部分，光电子发射研究已经证明，在某些情况下，相当出乎意料地，在令人惊讶的低光子能量定量大的非偶极效应，导致在光电子发射社区内的偶极近似的一般有效性的一个小的范式转变。拟议的研究将使用三种独特的自制仪器进行，一种用于使用飞行时间电子能量分析的气相光电发射，一种用于气体的高分辨率偏振X射线发射，第三种用于测量用X射线束照射的气相样品中的宏观电流。该计划的更广泛的影响涉及学生培训以及材料科学的应用。