Semiclassical Methods for the Evolution of Nonequilibrium Systems Undergoing Quantum Transitions

经历量子跃迁的非平衡系统演化的半经典方法

• 批准号: 0203041
• 负责人: Michael Herman
• 金额: $ 31.36万
• 依托单位: Tulane University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-06-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0203041&HistoricalAwards=false
• 关键词: Semiclassical; Methods; Evolution; Nonequilibrium; Systems

In this project funded by the Theoretical and Computational Chemistry Program of the Chemistry Division, Herman will develop numerically efficient and accurate semiclassical methods to evaluate quantum transition probabilities and correlation functions in nonequilibrium condensed-phase, gas-phase, and molecular-beam systems. These density-evolution methods require consideration of the full quantum nature of the evolution only for times on the order of the loss of quantum phase coherence. These methods are systematically correctable and provide an estimate of the calculational error at each level of approximation. The procedures will be tested on simple model problems for which exact quantum results can be obtained and then on problems for which experimental data is available. The results of calculations using these methods will also be compared with those obtained using other computational methods.At a time when experimental methods are able to characterize increasingly fast processes, it is imperative to develop theoretical formalisms that are capable of describing such processes. The work proposed here addresses that need. It further promises to provide a framework for analyzing and interpreting ultra-fast nonequilibrium processes in excited-state systems. The planned extension of the methods to systems that are far from equilibrium will allow simulation of new classes of chemical reactions.

在该项目由化学划分的理论和计算化学计划资助的项目中，Herman将开发数值和准确的半经典方法，以评估量子过渡概率和相关性功能，并在非平衡凝结相，气相相，气相相，分子束系统中。 这些密度进化方法需要考虑到量子相一致性损失的顺序，仅在时间上考虑进化的完整量子性质。 这些方法在系统上是可更正的，并提供了每个近似级别的计算误差的估计。 该过程将在可以获得精确量子结果的简单模型问题上进行测试，然后在可用的实验数据的问题上进行测试。 使用这些方法的计算结果也将与使用其他计算方法获得的计算结果进行比较。在实验方法能够表征越来越快的过程的时候，必须开发能够描述此类过程的理论形式主义。 这里提出的工作解决了需要的工作。 它进一步有望提供一个框架，用于分析和解释激发系统中超快速的非平衡过程。 计划扩展到远离平衡的系统的扩展将允许模拟新的化学反应。