RUI - Precision Measurements of the Fine Structure of High-Angular Momentum Rydberg States of Rotationally Excited Molecular Hydrogen

这项工作将获得对旋转激发的分子氢的高角动量里德堡态精细结构的精确测量。这项研究将导致精确地确定分子氢离子的基本性质，如多极矩、极化率和超精细常数。特别令人感兴趣的是H2+的基振态(v=0)的旋转激发态(R=2和3)的性质，这些性质到目前为止在实验上是无法获得的。由于缺乏稳定的激发态，目前对H2+的直接测量很少。然而，在一个大的接近圆形的轨道上，一个被激发的电子被束缚在一个离子核心上，可以作为一个非常灵敏的探测器来研究离子核心的电和磁性质。高角动量里德堡态满足这一标准，因此，对这些光谱的精确研究为探测离子的长程性质提供了机会。分子物理中的基本模型H2+已被理论界广泛研究，但精确的实验测量相对较少。对绝热近似以外的精确模型的需求正在增加，并且已经发展了几种理论方法。这项研究将为检验理论模型的准确性提供一个很好的途径。共振激发斯塔克电离光谱(RESIS)探测技术的一种新方法将允许首次测量H2的较高转动能级，这在以前的研究中是无法获得的，因为它们的自电离速率很快。这项工作将提供与H2+理论进展相关的精确测量，这在其他领域是必要的，如超冷分子和星际化学。新的测量还将立即改进现有的最好的H2+光谱测量。这项试验计划将在三个层面产生广泛影响。首先，总体来说，纽约州立大学弗雷多尼亚分校的本科生将受到积极影响，因为他们可以通过积极研究人员的建模、将当前研究成果融入课程作业、积极参与研究以及在多个层面上展示研究成果的经验来获得积极的影响。L·里德伯格说，对高密度的精细结构进行精确测量的研究为学生提供了在研究实验室中非常普遍地使用几种类型的设备获得经验的机会。此外，对这些近乎经典的高L里德堡系统的理论分析，可以被一个高水平的本科生理解。它清楚地展示了量子力学中微扰理论的使用，以及学生在典型的电学和磁学课程中会学到的几个概念，如多极展开。这项研究项目将用于在PI的本科生课堂上讨论各种主题，课程范围从基于代数的物理到400级物理课程。其次，这项研究项目的资助将有助于建立一个新的教员研究人员的职业生涯，增加校园内的实验研究，培养物理系和化学系之间的跨学科研究兴趣，并进一步扩大原子、分子和光学物理在小型本科院校的存在。第三，一所地处乡村的公立高等教育大学是K-16教育渠道的一部分，这项研究对STEM渠道中代表性不足的本科生产生了积极影响，如妇女、通过社区学院进入高等教育并通过公共资助的地区大学继续学习的经济困难学生、第一代大学生以及来自农村和地理偏远地区的学生。在这一农村地区的当地社区学院和/或其他区域机构的演讲积极地将这项研究的影响扩大到这一未得到充分服务的地区。

This work will obtain precise measurements of the fine structure of high-angular momentum Rydberg states of rotationally excited molecular hydrogen, H2. This study will lead to precise determinations of such fundamental properties of the molecular hydrogen ion as multipole moments, polarizabilities and hyperfine constants. Of particular interest are the properties of the rotationally excited states (R=2 and 3) of the ground vibrational state (v=0) of H2+ that have thus far been experimentally inaccessible. There are few existing direct measurements of H2+ because of the lack of stable excited states. However, an excited electron, bound to an ion core, in a large nearly circular orbit can act as a very sensitive probe to investigate electric and magnetic properties of the ion core. High angular momentum Rydberg states meet this criterion and, therefore, precise studies of these spectra afford the opportunity to detect long-range properties of the ion. The basic model in molecular physics, H2+, has been studied extensively by theorists, but there are comparatively few precise experimental measurements. The need for accurate models beyond the adiabatic approximation is increasing, and several theoretical approaches have been developed. This study will provide an excellent avenue to test the accuracy of the theoretical models. A novel approach to the detection techniques of Resonant Excitation Stark Ionization Spectroscopy (RESIS) will allow the first measurements of the higher rotational levels of H2 that were unattainable in previous studies due to their fast autoionization rates. This work will provide precise measurements relevant to the advances in H2+ theory, which are necessary in other areas such as ultracold molecules and interstellar chemistry. The new measurements will also provide immediate improvement to the best existing spectral measurement in H2+. The experimental program will have broad impact at three levels. First, undergraduate students at State University of New York at Fredonia in general would be positively impacted though the modeling of an active researcher, infusion of current research into course work, active participation in research, and experience in presenting research results at multiple levels. Studies in the precise measurement of the fine structure of high-L Rydberg states offers students the opportunity to gain experience with several types of equipment used quite universally in research labs. In addition, the theoretical analysis of these nearly classical high-L Rydberg systems can be understood by an upper-level undergraduate student. It clearly demonstrates the use of perturbation theory in quantum mechanics, and several concepts a student would learn in a typical electricity and magnetism course, such as the multipole expansion. This research project will be used for discussion of various topics in the PI's undergraduate classroom, in a range of courses from algebra-based physics to 400-level physics courses. Second, the funding of this research program will help establish the career of a new faculty researcher, increase the on-campus experimental research, develop interdisciplinary research interests between the Departments of Physics and Chemistry, and further expand the presence of atomic, molecular, and optical physics at small undergraduate institutions. Third, the research at a rurally situated public university of higher education, which is part of the K-16 educational pipeline, positively impacts undergraduate students who are underrepresented in the STEM pipeline such as women, economically disadvantaged students who enter higher education through community college and continue through publicly funded regional universities, first generation college students, and students who come from rural, geographically isolated areas. Presentations at local community colleges and/or other regional institutions in this rural area positively extend the impact of this research into this under-served area.