Quantum Wavepacket Dynamics Techniques: Theory and Application to Condensed Phase Systems

在化学学部理论与计算化学项目的资助下，Coalson教授将开发用于计算量子多体系统动态演化的波包方法，并将这些方法应用于凝聚态光谱中的几个问题。计算将有助于理解这些明显依赖于量子效应的系统中的速率过程。要研究的问题将包括：分子吸附物（例如，CH3Br和NO）的光解吸截面，以及牛胰腺tripsin抑制剂蛋白的共振拉曼激发谱。所采用的主要技术是时变哈特里网格法，该方法将完整的多体系统波函数分解为各个子系统的低维块。这种近似适用于处理上述应用中所要求的亚皮秒动力学。为了处理较长时间的过程，需要超过Hartee水平的精度。首席研究员将开发算法，与时变Hartee网格解决方案一起进行配置交互。这些算法将引入波包之间的直接关联，这些波包表示整个系统被划分为各个子系统。

With this grant in the Theoretical and Computational Chemistry Program of the Chemistry division, Professor Coalson will develop wavepacket methods for computing the dynamical evolution of quantum many-body systems and will apply these methods to several problems in condensed phase spectroscopy. The computations will aid in the understanding of rate processes in these systems which explicitly depend on quantum effects. The problems to be investigated will include: photodesorption cross sections of molecular adsorbates (e.g., CH3Br and NO), and resonance raman excitation profiles of the bovine pancreatic tripsin inhibitor protein. The principle technique to be employed is the time-dependent Hartree grid method which involves factorization of the complete many-body system wave function into low dimensional pieces for various subsystems. This approximation is suitable for treating subpicosecond dynamics as required in the above applications. In order to treat longer time processes, accuracy beyond the Hartee level will be necessary. The principal investigator will develop algorithms to do configuration interaction in conjunction with the time-dependent Hartee grid solutions. These algorithms will introduce direct correlation between wavepackets representing the various subsystems into which the overall system has been partitioned.