Theoretical investigation of molecule-intense laser interactions using quantum chemical approaches

该奖项由2009年美国复苏和再投资法案(公共法律111-5)资助。超快强激光可以发展成为成像电子结构、探测超快动力学以及控制电子布居和分子碎裂的强大工具。到目前为止，这些应用的原理验证实验只对一小部分分子进行了演示。对强激光-分子相互作用的理论理解对于推广这些应用是至关重要的，并且一直局限于过于简化的模型。这项工作探索了两种重要的相互作用的量子化学(QC)方法：多光子电离和高次谐波产生。为了正确地处理它们，必须解决高激发电子态和多电子效应的牵涉。这超出了只处理基态或低激发态的QC方法的常规应用。将进行一系列基准计算，以验证这些方法并确定主导这些过程的物理因素。在理论层面上可能改进的方法将与两位欧洲理论化学家合作。该项目将对强场分子物理和理论化学产生影响。这将有助于开发利用最先进的激光研究化学反应的新工具。此外，它还将融入蒙大拿大学的本科物理化学教育。三年级的学生将第一次体验计算化学，以加深他们对电子结构和物质-辐射场相互作用的理解。

AbstractThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Ultra-fast intense lasers can be developed into powerful tools for imaging electronic structures, probing ultra-fast dynamics, and controlling the electron population and molecular fragmentation. So far proof-of-principle experiments for these applications have been demonstrated for only a small number of molecules. Theoretical understanding of the intense laser-molecule interaction is crucial for the generalization of these applications and it has been limited to over-simplified models. This work explores quantum chemical (QC) methods for two important types of such interactions: multiphoton ionization and high harmonic generation. To properly treat them, the involvement of highly excited electronic states and many-electron effects have to be addressed. This is beyond conventional applications of the QC methods that treat only ground or low-lying excited states. A series of benchmark calculations will be performed to validate the methods and to identify the physics that dominates these processes. Possible improvement of the methods at theoretical level will be in collaboration with two European theoretical chemists. This project will have an impact in both strong field molecular physics and theoretical chemistry. It will help the development of new tools to study chemical reactions with state of the art lasers. In addition, it will also be integrated into the undergraduate physical chemistry education in the University of Montana. Junior year students will have their first experience with computational chemistry to enhance their understanding of electronic structure and matter-radiation field interactions.