Bond Dissociation Energies and Electronic Structure of Small Transition Metal and Lanthanide Molecules

过渡金属和镧系小分子的键解离能和电子结构

• 批准号: 2305293
• 负责人: Michael Morse
• 金额: $ 51.5万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-15 至 2026-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2305293&HistoricalAwards=false
• 关键词: Bond; Dissociation; Energies; Electronic; Structure

With support from the Chemical Structure, Dynamics, and Mechanisms-A (CSDM-A) Program in the Division of Chemistry, Professor Michael Morse of the University of Utah is using laser spectroscopy to study the electronic structure and chemical bonding in small molecules that contain d- and f-block metals, with emphasis on providing highly precise values of bond dissociation and ionization energies. These measurements will be useful for developing accurate and efficient computational methods for larger systems relevant to the catalytic and technological applications of the d- and f-block elements. Dr. Morse will examine the broad trends in chemical bonding as one moves across the periodic table in this work, and will investigate whether the dissociation energies of metals bonded to chemically related p-block elements, such as silicon and germanium, are strongly correlated. Professor Morse and his students will use resonant two-photon ionization spectroscopy to study neutral d- and f-block molecules, and cryo-cooled ion photodissociation experiments to study metal-containing cations. In addition to training the graduate students who are directly involved in this project, Dr. Morse also organizes a biannual workshop for high school chemistry teachers, where he presents on physical chemistry topics that they have selected. Other speakers also present on chemical education research and educational psychology.In this project, the Morse group will employ laser ablation of a metal sample in a pulsed supersonic expansion of helium with small amounts of a reactant gas to generate a molecular beam of the species of interest. They will then use a one laser pulse, which is scanned, to excite the molecule electronically and a second laser pulse to ionize the molecule. Ions will then be detected using time-of-flight mass spectrometry. Molecules with a high density of electronic states, such as the open d- and f-subshell molecules, fall apart on a subnanosecond time scale when they are excited above their dissociation energy, causing a sharp drop in ion signal. This provides a highly precise measurement of the bond energy. The Morse team is also able to use the high density of electronic states in these species to measure ionization energies to high precision. Employing a different instrument, the research team is using similar methods to measure the threshold for dissociation in a range of d- and f-block cryo-cooled ions. The bond dissociation energies of the neutral molecules and their cations can then be combined with the ionization energies of the neutral molecules and of the metal atoms using a thermochemical cycle to confirm the accuracy of all four measured values. These studies are likely to be particularly useful for the development of density functional theory methods for accurate computations of molecules containing the d- and f-block elements.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在化学系化学结构、动力学和机理 A (CSDM-A) 项目的支持下，犹他大学的 Michael Morse 教授正在利用激光光谱研究小分子中的电子结构和化学键合，这些小分子含有d 区和 f 区金属，重点是提供高精度的键离解和电离能值。这些测量将有助于为与 d 区和 f 区元素的催化和技术应用相关的大型系统开发准确有效的计算方法。 Morse 博士将在这项工作中研究化学键在元素周期表中的广泛趋势，并将研究与化学相关的 p 区元素（例如硅和锗）键合的金属的解离能是否密切相关。 Morse 教授和他的学生将使用共振双光子电离光谱来研究中性 d 区和 f 区分子，并使用低温冷却离子光解离实验来研究含金属阳离子。除了培训直接参与该项目的研究生外，莫尔斯博士还为高中化学教师组织了一年两次的研讨会，在会上他介绍了他们选择的物理化学主题。其他演讲者还介绍了化学教育研究和教育心理学。在该项目中，莫尔斯小组将在氦气脉冲超音速膨胀和少量反应气体中采用激光烧蚀金属样品，以产生以下物质的分子束：兴趣。然后，他们将使用一个激光脉冲进行扫描，以电子方式激发分子，并使用第二个激光脉冲电离分子。 然后使用飞行时间质谱法检测离子。具有高电子态密度的分子，例如开放的 d 和 f 亚壳分子，当它们被激发到高于其解离能时，会在亚纳秒时间尺度上分解，导致离子信号急剧下降。这提供了键能的高精度测量。莫尔斯团队还能够利用这些物种中的高密度电子态来高精度测量电离能。研究团队采用不同的仪器，使用类似的方法来测量一系列 d 和 f 块低温冷却离子的解离阈值。然后可以使用热化学循环将中性分子及其阳离子的键解离能与中性分子和金属原子的电离能结合起来，以确认所有四个测量值的准确性。这些研究可能对于开发密度泛函理论方法特别有用，用于精确计算包含 d 和 f 块元素的分子。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力评估进行评估，被认为值得支持。优点和更广泛的影响审查标准。

项目成果

Adiabatic ionization energies of RuC, RhC, OsC, IrC, and PtC

RuC、RhC、OsC、IrC 和 PtC 的绝热电离能

• DOI: 10.1063/5.0194848
• 发表时间: 2024-02
• 期刊: The Journal of Chemical Physics
• 作者: Merriles, Dakota M.;Barrera;Knapp, Annie S.;Morse, Michael D.
• 通讯作者: Morse, Michael D.