Theoretical Studies of Spectral Signatures of Large Amplitude Vibrational Motions

州立大学俄亥俄州的安妮麦考伊获得了化学系化学理论、模型和计算方法项目的一项奖励，以开发理解分子光谱所需的理论和计算工具，其中分子中的原子经历大幅度运动。这项工作特别关注质子化和氢键系统。 这类分子可以在我们的大气层中找到，也可以在星际介质中找到。 这样的分子系统也提供了理解离子在水中的溶剂化作用的原型。 实验学家使用 振动光谱 来研究这些分子。 在天体化学的情况下，振动光谱学提供了研究化学成分的最佳方法。 然而，与许多常见的分子不同，这些系统中的键合很弱。 大多数已经开发出来的用于预测和解释 旋转/振动光谱学不适用于它们。 通过开发这些新方法，麦考伊和她的研究小组正在解决这一缺陷。 这些研究的结果将被用来开发光谱和结构之间的联系和键合。 麦考伊和她的研究小组与实验研究小组合作，对所有这些项目。该研究计划为本科生和研究生提供教育和研究机会。 麦考伊非常积极地鼓励妇女和其他代表性不足的群体从事科学事业。特别感兴趣的是旋转和振动运动之间的相互作用。 为此，麦考伊小组正在开发几种基于蒙特卡罗的技术来探测这些相互作用。 所提出的工作涉及的扩散蒙特卡罗方法，重点是扩展的范围内的属性，可以使用这种一般的方法计算。 此外，他们采用了一种基于Monte Carlo采样的潜在表面的方法，以加深对氢键系统中光谱特征加宽的起源的理解。 具体的应用包括分子，特别是H5+和CH 5+，这是天体化学的利益，以及一些研究，探测氢键的光谱特征的起源。

Anne McCoy of Ohio State University is supported by an award from the Chemical Theory, Models and Computational Methods program in the Chemistry division to develop theoretical and computational tools needed to understand the spectra of molecules in which the atoms in the molecules undergo large amplitude motions. The work has a particular focus on protonated and hydrogen bonded systems. This class of molecules can be found close to home in our atmosphere and also far away in the interstellar medium. Such molecular systems also provide prototypes to understand the solvation of ions in water. Experimentalists use vibrational spectroscopy to study these molecules. In the case of astrochemistry, vibrational spectroscopy provides the best method for studying chemical composition. Unlike many common molecules, however, the bonding in these systems is weak. Most of the models that have been developed to predict and interpreted rotation/vibration spectroscopy do not apply to them. By developing these new approaches, McCoy and her research group are addressing this deficiency. The results of these studies will be used to develop connections between spectra and structure and bonding. McCoy and her research group collaborate with experimental research groups on all of these projects. This research program provides educational and research opportunities for both undergraduates and graduate students. McCoy is very active in encouraging women and other members of under-represented groups to pursue careers in science. Of particular interest is the interaction between rotation and vibration motions. To this end, the McCoy group is developing several Monte Carlo-based techniques to probe these interactions. Much of the proposed work involves the Diffusion Monte Carlo approach, with an emphasis on extending the range of properties that can be calculated using this general approach. In addition, they employ an approach based on Monte Carlo sampling of potential surfaces to deepen the understanding of the origins of the broadening of spectral features in hydrogen bonded systems. Specific applications include molecules, specifically H5+ and CH5+ that are of astrochemical interest, as well as several studies that probe the origins of spectral signatures of hydrogen bonding.