Laser Control of Molecular Conformation as an Avenue for Practical Laser Chemistry

弗吉尼亚大学的布鲁克斯·佩特获得了实验物理化学项目的职业资助，以启动实用激光化学中分子构象的激光控制研究。这些研究的目标是选择性地填充单个分子构象结构，从而提高沿着所需途径的反应速度。在双激光实验中，分子首先被激发到一个能区，在这个能区，围绕不同构象极小值的振动态通过分子内振动能量重新分配(IVR)耦合。由于振动频率取决于构象，然后选择第二个(共振)激光来刺激发射到较低的状态。这种较低的能量状态位于IVR的起始能量以下，因此最终结构局限在一个所需构象周围。人们对振动激发的分子可能呈现的构象知之甚少，但反应速度强烈地依赖于构象结构。这些技术将提供这种类型的第一批信息，因此可能会带来真正突破性的结果。Pate教授职业奖励的教育部分将强调为那些对物理化学职业感兴趣的学生开发一门类似于“研究培训”课程的物理化学课程，在课程中更好地利用计算机，例如用于处理问题的符号数学软件，以及在实验室课程中纳入现代研究仪器。

Brooks Pate of the University of Virginia has been awarded a CAREER grant in the Experimental Physical Chemistry Program to initiate studies of laser control of molecular conformations for practical laser chemistry. The goal of these investigations is to selectively populate a single molecular conformational structure, resulting in an enhanced reaction rate along the desired pathway. In the two-laser experiment, molecules are first excited to an energy region where the vibrational states localized around the different conformational minima are coupled through intramolecular vibrational energy redistribution (IVR). Since the vibrational frequencies depend on conformation, a second (resonant) laser is then selected to stimulate emission to a lower state. This lower energy state lies below the onset energy for IVR, hence the final structure is localized around the one desired conformation. Little is known about the conformations that a vibrationally excited molecule can assume, yet reaction rates are strongly dependent on the conformational structure. These techniques will provide the first information of this type and hence may lead to truly ground-breaking results. The educational component of Prof. Pate's CAREER award will emphasize the development of a physical chemistry course along the lines of a `research training` course for those students interested in physical chemistry careers, better utilization of computers in the curriculum, e.g., symbolic math software for problem manipulations, and incorporation of modern research instrumentation in the laboratory courses.