High Precision Energy Levels for the Simplest Polyatomic Molecule (H3+)

最简单多原子分子 (H3) 的高精度能级

• 批准号: 1404330
• 负责人: Benjamin McCall
• 金额: $ 25.08万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1404330&HistoricalAwards=false
• 关键词: Precision; Energy; Levels; Simplest; Polyatomic

H3+ is the simplest molecule with more than two atoms: it consists of three protons bound by two electrons. As such, it is an ideal benchmark system for testing state-of-the-art theoretical calculations of molecular energy levels. H3+ is significant not only for these fundamental reasons, but also because it has been widely observed in a variety of astronomical environments, including the atmospheres of Jupiter and Saturn and in clouds of gas between stars. These observations are made by precisely determining the colors of light that are emitted by the molecule, a technique called "spectroscopy". The latest calculations can reproduce the colors of H3+ to within the accuracy of current laboratory spectroscopy measurements, so further progress in theoretical development will require improvements in the laboratory instrumentation. The group supported by this grant plans to utilize a novel instrument that will allow them to measure H3+ colors to a precision that is 10,000 times better than previous work. The resulting dataset will serve as an enduring benchmark for high-level theoretical calculations, and will also assist astronomical observations of this important molecule. In the long run, it is anticipated that this work will help in the development of improved methods of controlling chemical reactions and thereby advance a significant fraction of the industrial sector.The work will use a recently-constructed instrument that allows routine sub-Doppler spectroscopy of molecular ions. This instrument will be upgraded to achieve a precision of approximately 30 kiloHertz, or one-millionth of a wavenumber, and then used to record high-precision spectra of H3+ in the mid-infrared. An analysis using combination differences and effective Hamiltonian fitting will be used to produce a set of experimentally determined energy levels of H3+, with a precision that is approximately four orders of magnitude better than previous work. These precise energy levels will permit the direct testing of non-adiabatic corrections to the Born-Oppenheimer approximation, various empirical corrections, and ultimately calculations of the Lamb shift for H3+.

H3+是具有两个以上原子的最简单分子：它由三个由两个电子结合的质子组成。 因此，它是测试分子能级的最新理论计算的理想基准系统。 H3+不仅出于这些根本原因，而且是因为它在各种天文环境中被广泛观察到，包括木星和土星的大气以及恒星之间的气体云。 这些观察结果是通过精确确定分子发出的光的颜色（一种称为“光谱”的技术。 最新的计算可以将H3+的颜色重现为当前实验室光谱测量的准确性，因此理论发展的进一步进展将需要改善实验室仪器。 该赠款计划支持的小组利用一种新颖的仪器，可以使他们可以测量H3+颜色的精度，比以前的工作要好10,000倍。 所得的数据集将作为高级理论计算的持久基准，还将有助于对这一重要分子的天文观察。 从长远来看，预计这项工作将有助于开发改进的控制化学反应的方法，从而促进大部分工业领域的一部分。该工作将使用最近构造的仪器，以允许常规的分子离子子多普勒光谱。 该仪器将被升级，以达到约30千厄尔茨或波数的一百万个仪器的精度，然后用来记录中红外H3+的高精度光谱。 使用组合差异和有效哈密顿式配件的分析将用于产生一组实验确定的H3+的能量水平，其精度约为四个数量级，比以前的工作好了四个数量级。 这些精确的能量水平将允许直接测试非绝热的校正，以对出生的脑近似，各种经验校正以及最终计算H3+的羔羊偏移。