Theoretical and Computational Studies of Quantum Dynamical Processes in Condensed Matter Systems

格雷戈里·沃斯得到了理论和 计算化学计划继续他的理论发展 质心分子动力学（CMD）技术，并将其应用于一个 在凝聚相动力学领域的一些重要问题， 具有量子自由度的系统 CMD方法基于 计算费曼路径积分质心的轨迹使用经典的 分子动力学技术 然后将轨迹进行相关， 统计加权相空间费曼路径积分 质心密度 所得到的时间相关函数可以与 通过傅里叶变换到量子时间相关函数。 CMD 因此允许量子时间相关函数近似为 用类似于经典MD计算的数值努力来计算。 将研究几种应用。 质子移位 水和溶剂化和水合电子的扩散传输将 接受治疗 第二个研究领域涉及一个 凝聚相初值半经典动力学方法 系统. 这种方法将允许研究非平衡和 非绝热过程和非线性“系统浴”的处理 交互. 最后，激活量子动力学的正式处理 将致力于发展量子力学的新图景， 过渡态 气相化学系统已经研究了许多年， 优秀的理论和计算技术已经发展到 模仿他们的行为。最近的理论和计算方法 正在开发，使其有可能处理更复杂的浓缩 相位系统目前大多数理论模型都是经典的， 性质，不能处理额外的并发症， 量子效应沃斯的研究解决了这种额外程度的 复杂性，并提出了计算方法的发展 设计用于处理冷凝相系统，包括 各种量子自由度。

Gregory Voth is supported by a grant from the Theoretical and Computational Chemistry Program to continue his theoretical development of the Centroid Molecular Dynamics (CMD) technique, and to apply it to a number of important problems in the area of condensed phase dynamics of systems with quantum degrees of freedom. 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 calculation. Several applications will be investigated. Proton translocation in water and the diffusive transport of solvated and hydrated electrons will be treated. A second area of research involves the development of an initial value semiclassical dynamics approach for condensed phase systems. This approach would allow the study of both nonequilibrium and nonadiabatic processes, and treatment of nonlinear `system-bath` interactions. Finally, a formal treatment of activated quantum dynamics will be undertaken to develop a new picture of the quantum mechanical transition state. Gas phase chemical systems have been studied for a number of years, and excellent theoretical and computational techniques have been developed to model their behavior. More recently theoretical and computational methods are being developed that make it possible to treat more complex condensed phase systems. Most of the current theoretical models are classical in nature and cannot deal with the additional complications imposed by quantum effects. Voth's research addresses this additional degree of complexity and proposes the development of computational approaches designed to permit the treatment of condensed phase systems that include various quantum degrees of freedom.