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Exploring Spectral Signatures of Molecular Vibrations

探索分子振动的光谱特征

基本信息

批准号：
2154126
负责人：
Anne McCoy
金额：
$ 51万
依托单位：
University of Washington
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2022
资助国家：
美国
起止时间：
2022-05-01 至 2025-04-30
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2154126&HistoricalAwards=false
关键词：
Exploring Spectral Signatures Molecular Vibrations

项目摘要

Professor Anne B. McCoy of the University of Washington is supported by an award from the Chemical Theory, Models and Computational Methods (CTMC) program in the Division of Chemistry to develop new theoretical and computational tools that will be used to explore the manifestations of nuclear quantum effects in hydrogen-bonded systems. Hydrogen-bonding is ubiquitous, and there are often surprisingly large differences between properties of normal water (H2O) and heavy water (D2O). Many of these differences are attributed to the quantum mechanical nature of molecular vibrations. While knowing that these effects exist is easy to articulate, quantifying them is much more difficult. Anne McCoy and her research group develop tools for exploring quantum mechanical effects in molecular vibrations, and through collaborations with experimental groups has worked to enhance our understanding of these effects. The methods that she and her research group are developing can be applied to systems of up to 20 atoms that are small enough for detailed calculations and comparisons to spectroscopic experiments, but large enough to exhibit the types of nuclear quantum effects that affect properties of liquid water or ice. In parallel with this work, Anne McCoy and her group are developing tools that can be used by the community to implement the approaches she has. She is pursuing a variety of activities that focus on development of the next generation of physical chemists including mentoring students and promoting early career scientists through her roles as chair of the International Advisory Committee for the International Symposium on Molecular Spectroscopy and an officer of the American Physical Society’s Division of Chemical Physics.The supported work focuses on the development of vibrational perturbation theory and diffusion Monte Carlo approaches and using these approaches to explore the manifestations of nuclear quantum effects in hydrogen-bonded systems. The work on vibrational perturbation theory focuses on the development of approaches for identifying resonances and exploring the role of third and higher order corrections to the results obtained at second order (VPT2). A key feature of this work is the exploration of the impact of coordinates in which the Hamiltonian is expanded on the insights obtained from vibrational perturbation theory. The work on Diffusion Monte Carlo (DMC) focuses on the development of efficient procedures for evaluating the potential energies used in DMC using neural-network potentials, which are based on the geometries evaluated from small DMC simulations. These potential surfaces are then in larger DMC studies. A central application of these studies is an exploration of how nuclear quantum effects are manifested in water through studies of water clusters. This work focuses on probing relationships between spectra, large amplitude motions and how and why the structure of water and protonated water systems change with deuteration. A theme that underlies these studies is the development of versatile approaches that can be used to explore a broad range of systems, and to develop general understandings that provide broader insights in quantum effects in hydrogen bonding that extend beyond the specific systems that are being studied. The codes developed in this work are part of the PyVibDMC and PyVibPTn codes that Anne McCoy and her research group have been developing.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.

安妮B教授。华盛顿大学的麦考伊获得了化学系化学理论、模型和计算方法（CTMC）项目的一项奖励，以开发新的理论和计算工具，用于探索氢键系统中核量子效应的表现形式。氢键是普遍存在的，并且通常在正常水（H2O）和重水（D2O）的性质之间存在令人惊讶的巨大差异。这些差异中的许多归因于分子振动的量子力学性质。虽然知道这些影响的存在很容易表达，但量化它们要困难得多。安妮麦考伊和她的研究小组开发工具，探索分子振动中的量子力学效应，并通过与实验小组的合作，努力提高我们对这些效应的理解。她和她的研究小组正在开发的方法可以应用于多达20个原子的系统，这些原子足够小，可以进行详细的计算和与光谱实验进行比较，但又足够大，可以显示出影响液态水或冰性质的核量子效应类型。在这项工作的同时，安妮麦考伊和她的小组正在开发可供社区使用的工具，以实现她的方法。她正在从事各种活动，专注于下一代物理化学家的发展，包括指导学生和促进早期职业科学家，通过她担任国际分子光谱学研讨会国际咨询委员会主席和美国物理学会化学物理部官员的角色。支持的工作重点是振动微扰理论和扩散的发展蒙特卡罗方法，并利用这些方法来探讨氢键系统中的核量子效应的表现形式。振动微扰理论的工作重点是发展识别共振的方法，并探索三阶和高阶修正对二阶（VPT 2）结果的作用。这项工作的一个关键特点是探索坐标的影响，其中的哈密顿量扩展的见解从振动微扰理论。扩散蒙特卡罗（DMC）的工作重点是开发有效的程序，用于评估DMC中使用的势能神经网络潜力，这是基于从小型DMC模拟评估的几何形状。这些潜在的表面，然后在更大的DMC研究。这些研究的一个中心应用是通过对水分子团簇的研究来探索核量子效应在水中的表现。这项工作的重点是探索光谱之间的关系，大幅度运动和如何以及为什么水和质子化水系统的结构变化与氘。这些研究的一个主题是开发通用的方法，可用于探索广泛的系统，并发展一般的理解，提供更广泛的见解，在氢键的量子效应，扩展到正在研究的特定系统之外。这项工作中开发的代码是Anne麦考伊和她的研究小组一直在开发的PyVibDMC和PyVibPTn代码的一部分。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

项目成果

期刊论文数量（7）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Characterization of the Oxazolone and Macrocyclic Motifs in the b n ( n = 2–5) Product Ions from Collision-Induced Dissociation of Protonated Oligoglycine Peptides with Isomer-Selective, Cryogenic Vibrational Spectroscopy

使用异构体选择性低温振动光谱法表征质子化寡甘氨酸肽碰撞诱导解离的 b n ( n = 2â5) 产物离子中的恶唑酮和大环基序

DOI：
10.1021/jasms.3c00372
发表时间：
2024
期刊：
Journal of the American Society for Mass Spectrometry
影响因子：
3.2
作者：
Mohamed, Ahmed;Rana, Abhijit;Perez, Evan;Dahlmann, Franziska;Fry, Allison;Menges, Fabian S.;van Stipdonk, Michael;Jäger, Svenja;Boyer, Mark A.;McCoy, Anne B.
通讯作者：
McCoy, Anne B.

Evidence of anharmonicity in the vibrational spectrum of protonated ethylene

质子化乙烯振动谱非谐性的证据