Development and application of Quantum wavepacket ab initio molecular dynamics for study of vibrational properties in hydrogen bonded systems

印第安纳大学的斯里尼瓦桑·艾扬格（Srinivasan Iyengar）获得了化学理论、模型和计算方法项目的资助，继续开发组合量子波包分子动力学技术，该技术最初是由艾扬格小组在上一个资助周期中开发的。这项工作解决了现代理论化学物理学中最具挑战性的问题之一：电子结构和核动力学的联合计算研究。QWAIMD通过量子波包动力学和从头算分子动力学的协同作用，涉及电子和原子核的同步动力学。它允许计算实现电子和原子核动力学的“自包含黑箱”技术，而不需要先验的势能面知识。这些新方法被用于研究氢键团簇的振动特性。如何将分子中电子固有的量子力学描述与分子运动描述结合起来，是现代理论化学中最具挑战性的问题之一。分子运动通常用经典力学处理，但在许多情况下，量子力学处理是必要的。这项工作解决了如何同时实现电子和原子核的量子处理的问题。如果成功，这项工作将对包括生物酶系统中的氢转移反应、大气反应中的溶剂化辅助动力学和燃料电池中的氢转移在内的许多重要应用主题的适当描述的发展产生广泛的影响。因此，这项工作预计将对生物学、大气科学和材料化学产生更广泛的影响，并通过PI的广泛推广工作，对少数族裔学生产生更广泛的影响。

Srinivasan Iyengar of Indiana University is supported by an award from the Chemical Theory, Models and Computational Methods program to continue the development of a combined quantum wavepacket molecular dynamics technique originally developed by the Iyengar group during the previous funding cycle. This work addresses one of the most challenging problems in modern theoretical chemical physics: the combined computational study of electronic structure and nuclear dynamics. QWAIMD involves the simultaneous dynamics of electrons and nuclei though the synergy of quantum wavepacket dynamics and ab initio molecular dynamics. It allows the computational implementation of a "self-contained black-box" technique for dynamics of electrons and nuclei that does not require a priori knowledge of the potential energy surface. These novel methods are being used to study the vibrational properties of hydrogen bonded clusters. One of the most challenging issues in modern theoretical chemistry is determining the proper way to combine the inherently quantum mechanical description of the electrons in molecules with the description of molecular motion. Molecular motion is commonly treated using classical mechanics but in many cases quantum mechanical treatment is necessary. This work addresses the issue of how simultaneous quantum treatment of electrons and nuclei can be achieved. If successful, the work will have wide impact on the development of proper descriptions of a number of important application topics including hydrogen transfer reactions in biological enzyme systems, solvation assisted kinetics in atmospheric reactions and hydrogen transfer in fuel cells. The work is, thus, expected to have a broader impact in biology, atmospheric science and materials chemistry and, through the PI's extensive outreach work, on students from under-represented minorities.