Theoretical Descriptions of Molecular Dynamics and Spectroscopy in Condensed and Gas Phases

威斯康星大学麦迪逊分校的埃德温·西伯特（Edwin Sibert）在理论与计算化学项目的支持下，利用经典与量子技术相结合的方法，研究气相和液相中多原子分子的能量流动。研究将包括动力学事件，包括振动弛豫、质子转移反应和凝聚相中的振动预解离。目标是建立这些过程的可靠分子模型。模型结果应与实验观测结果一致，并有望为今后的实验提供指导。将对三溴甲烷和氘化三溴甲烷的混合物进行研究，目的是绘制出能量如何在分子之间传播。此外，甲酸二聚体，双质子转移的典型例子，将研究在气相和液相。最后，将研究缩合相的振动预解离，特别是氢键低聚物的预解离。超快激光光谱学的最新进展使化学家能够以前所未有的时间和尺寸分辨率探测分子事件的展开。当这些实验与从原子论角度出发的深思熟虑的理论建模相结合时，对原子之间的力如何控制能量流动有了重要的见解。这项研究将在量化这些想法方面取得进展，并为这些力量所导致的事件开发预测模型。从长远来看，这些模型对于在分子水平上成功地模拟大气、燃烧和生物过程是必不可少的。

Edwin Sibert of the University of Wisconsin, Madison, is supported by the Theoretical and Computational Chemistry Program to study energy flow in polyatomic molecules in both gas and liquid phases using combined classical and quantum techniques. The research will encompass dynamical events that include vibrational relaxation, proton transfer reactions, and vibrational predissociation in the condensed phase. The objective is to develop robust molecular models of these processes. The model results should be consistent with experimental observations, and are expected to serve as a guide for future experimentation. Mixtures of bromoform and deuterated bromoform will be investigated with the goal of mapping out how energy travels between molecules. As well, formic acid dimer, a prototypical example of double proton transfer, will be studied in the gas and liquid phases. Finally, vibrational predissociation in the condensed phase, and in particular predissociation of hydrogen bonded oligomers, will be investigated.Recent advances in an ultrafast laser spectroscopies enable chemists to probe the unfolding of molecular events with unprecedented time and size resolution. When these experiments are combined with thoughtful theoretical modeling from an atomistic perspective, significant insights are attained on how energy flow is controlled by forces between atoms. This research will make progress toward quantifying these ideas and developing predictive models for the events that occur as a result of these forces. Such models are essential, in the long term, for successful modeling of atmospheric, combustion, and biological processes at a molecular level.