Geometry of the transition state in the driven dynamics of molecular and spintronic systems

分子和自旋电子系统驱动动力学中过渡态的几何结构

• 批准号: 389136112
• 负责人: Professor Dr. Jörg Main
• 金额: --
• 依托单位: 1. Institut für Theoretische Physik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/389136112?language=en
• 关键词: Geometry; transition; state; driven; dynamics

Transitions of systems between different states take place in many physical and chemical systems. The mechanism, how a reaction takes place, the reaction rate, and in particular possibilities to control the reaction are of high interest. Transition state theory (TST)allows to describe activated reactions qualitatively as well as quantitatively. A field of growing interest over the recent years are time-dependent systems which are externally driven by noise and/or external fields, because they allow one to actively control the reaction rates and pathways. Time-dependent extensions of TST are capable of exactly describing such driven systems, however, so far, the developed methods are restricted to simple, one-dimensional model systems. The aim of the project is the development of methods which can be applied to realistic systems with finite reactant basins and many degrees of freedom, and, in particular, allow to exactly describe the reaction dynamics of time-dependent, driven, and high-dimensional activated systems. For this purpose, it is the first goal to define and construct an appropriate, time-dependent and high-dimensional dividing surface which uniquely separates reactants and products at all times. A second goal is the application of the developed methods to the fields of chemistry and physics with examples including, e.g., the LiCN isomerization reaction and spin-torque-switching in ferromagnets. For these systems we want to describe globally and exactly the time-dependent reaction dynamics, determine the respective reaction rates, and control the reaction pathways by applying an appropriate external driving.

系统在不同状态之间的转变发生在许多物理和化学系统中。机理，反应如何发生，反应速率，特别是控制反应的可能性是人们非常感兴趣的。过渡态理论（TST）允许定性和定量地描述活化反应。近年来人们越来越感兴趣的一个领域是由噪声和/或外部场驱动的时间依赖系统，因为它们允许人们主动控制反应速率和途径。时间相关的TST扩展能够准确地描述这种驱动系统，然而，到目前为止，开发的方法仅限于简单的一维模型系统。该项目的目的是开发可应用于具有有限反应物盆地和许多自由度的现实系统的方法，特别是允许准确描述时间相关，驱动和高维活化系统的反应动力学。为此，第一个目标是定义和构建一个合适的、与时间相关的、高维的分割面，它在任何时候都能唯一地分离反应物和生成物。第二个目标是将开发的方法应用于化学和物理领域，例如，铁磁体中的LiCN异构化反应和自旋转矩开关。对于这些系统，我们希望全局准确地描述随时间变化的反应动力学，确定各自的反应速率，并通过应用适当的外部驱动来控制反应路径。