Theoretical and Computational Studies of Quantum Dynamical Processes in Condensed Matter

凝聚态量子动力学过程的理论与计算研究

• 批准号: 0317132
• 负责人: Gregory Voth
• 金额: $ 42.9万
• 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: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0317132&HistoricalAwards=false
• 关键词: Theoretical; Computational; Studies; Quantum; Dynamical

Professor Gregory A. Voth, of the University of Utah, is supported by the Theoretical and Computational Chemistry Program to perform theoretical studies on excited-state reaction dynamics, surface chemistry and condensed-phase processes. Current focus is on extending and further developing the centroid molecular dynamics method (CMD). The CMD method is based on computing trajectories of Feynman path integral centroids using classical molecular dynamics techniques. The trajectories are then correlated and statistically weighted with the phase space Feynman path integral centroid density. The resulting time correlation function can be related by Fourier transform to the quantum time correlation function. CMD therefore allows quantum time correlation functions to be approximately calculated with a numerical effort similar to a classical MD calculations. Such methods are aimed at understanding proton transport in aqueous environments and in the simulation of hydrated electrons. Specific improvements under development include: (1) the development of a numerically exact algorithm to provide corrections to the CMD dynamics, (2) the incorporation of the semiclassical initial value representation for centroid dynamics propagation, (3) simplifying the CMD approach using Gaussian representations, including nonadiabatic dynamics of the electronic degrees of freedom, (4) inclusion of nonlinear correlation functions, and (5) inclusion of Fermi-Dirac statistics.Proton transfer in complex condensed phase systems is a fundamental aspect of many biological processes such as photosynthesis in plants and breathing in animals. The complete understanding of these processes is currently absent and in need of sophisticated theoretical treatments that are capable of accounting for the quantum-mechanical behavior of electrons and the nearly classical motion of protons. Methods developed here are well suited for dynamical descriptions associated with nearly classical proton transfer. Further understanding of these processes is requisite to the development of biomimetic materials for solar energy conversion, carbon sequestration and possibly biologically inspired environmentally friendly catalysis. Similar dynamics are of interest to atmospheric chemistry since protonated water clusters are abundant in the upper atmosphere. Research is also imparted to various communities through the training of graduate and postgraduate researchers.

犹他大学的Gregory A. Voth教授得到了理论和计算化学计划的支持，以对激发反应动态，表面化学和凝结相过程进行理论研究。当前的重点是扩展和进一步开发质心分子动力学方法（CMD）。 CMD方法基于使用经典分子动力学技术的Feynman路径积分质心的计算轨迹。 然后将轨迹与相位空间Feynman路径积分质心密度相关，并在统计上加权。 所得的时间相关函数可以通过傅立叶变换到量子时间相关函数相关。 因此，CMD允许使用类似于经典MD计算的数值努力来近似计算量子时间相关函数。 此类方法旨在了解在水性环境中和水合电子的模拟中的质子传输。 开发中的具体改进包括：（1）开发一种数值确切的算法，以对CMD动态进行更正，（2）将半经典初始值表示以质心动态传播的形式，（3）使用高斯代表的CMD方法来简化cmd的方法，包括高斯的非整合性范围，以及（4）自由度范围，（4）自由度的动态，（4）（4）（4）（4）（4）（4）（4）（4）（4）（4）（4） Fermi-Dirac统计。复杂凝结相系统中的普罗顿转移是许多生物学过程的基本方面，例如植物中的光合作用和动物的呼吸。目前对这些过程的完整理解是不存在的，需要精致的理论处理，这些处理能够考虑电子的量子力学行为和质子的近乎经典运动。 此处开发的方法非常适合与几乎经典质子转移相关的动力描述。 对这些过程的进一步了解是开发用于太阳能转化，碳固换以及可能受到生物启发的环保催化的仿生材料的必要条件。 类似的动力学对大气化学感兴趣，因为质子化的水簇在上层大气中很丰富。 通过培训研究生和研究生的研究人员，研究还将为各个社区提供。