Nonadiabatic Molecular Dynamics in Condensed Systems

凝聚系统中的非绝热分子动力学

• 批准号: 9521793
• 负责人: David Coker
• 金额: $ 32.49万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-11-15 至 1999-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9521793&HistoricalAwards=false
• 关键词: Nonadiabatic; Molecular; Dynamics; Condensed; Systems

David Coker is supported by a grant from the Theoretical and Computational Chemistry Program to continue his research in nonadiabatic molecular dynamics in condensed systems. Coker is combining nonadiabatic switching formalism with surface hopping theory to study energy redistribution between quantum and classical subsystems. This has resulted in a new approach for treating nonadiabatic dynamics in condensed phase systems. Additional new methods will be developed for simulating systems with few nonadiabatic quantum degrees of freedom in the presence of a classical bath degrees of freedom. Applications which explore nuclear nonadiabaticity include: 1) studies of the effects of solvent density on the nonadiabatic rotational dynamics of hydrogen molecule in solution and the influence they have on rotational Raman linewidths; 2) the influence of nonadiabatic dynamics and tunneling on transport of hydrogen molecule in ice; and 3) studies of solution phase intermolecular proton transfer reactions and the effects of solvent polarization and planarity on tunneling and nonadiabaticity of proton dynamics. Electronic nonadiabaticity in solution phase reactions will be studied by the introduction of a semi-empirical valence bond approach called diatomics in molecules. This approach will be used to study early time nonadiabatic dynamics after photoexcitation of diatomic iodine, diatomic iodine anion, and methyl iodide in various molecular solvents. Since most industrial synthetic processes occur in solution, it is important to gain an increased understanding of the influence which solvent has on fundamental chemical processes in solvated systems including molecular transport, proton transfer, and electronic excitation. This theoretical research will lead to an improved understanding of the factors which influence chemical reactions in solution.

David Coker获得了理论与计算化学项目的资助，继续他在凝聚态系统中非绝热分子动力学的研究。Coker将非绝热开关形式论与表面跳变理论相结合，研究量子子系统与经典子系统之间的能量再分配。这为处理凝聚相系统的非绝热动力学提供了一种新的方法。另外的新方法将开发用于模拟系统的非绝热量子自由度很少，在一个经典的浴自由度的存在。研究核非绝热性的应用包括：1)研究溶剂密度对溶液中氢分子非绝热旋转动力学的影响及其对旋转拉曼线宽的影响；2)非绝热动力学和隧道效应对冰中氢分子输运的影响；3)溶液相分子间质子转移反应的研究以及溶剂极化和平面性对质子动力学隧穿性和非绝热性的影响。溶液反应中的电子非绝热性将通过引入一种称为分子双原子的半经验价键方法来研究。该方法将用于研究双原子碘、双原子碘阴离子和碘化甲酯在不同分子溶剂中光激发后的早期非绝热动力学。由于大多数工业合成过程都是在溶液中进行的，因此有必要进一步了解溶剂对溶剂化系统中基本化学过程的影响，包括分子传递、质子转移和电子激发。这一理论研究将使人们更好地了解影响溶液中化学反应的因素。