Achieving Selectivity in a Chemical Reaction Process Using Reactant Orientation via Electric Fields

美国俄勒冈州立大学的孔伟（Wei Kong）获得了一项“职业生涯”实验物理化学项目的资助，研究定向化学反应物以实现反应选择性的方法。目标是有选择地切割指定的化学键，而竞争途径的影响最小。利用超声速分子束和中等电场，观察了极性反应物的取向。然后，定向化学键将被线性偏振激光选择性地解离。根据取向分子跃迁偶极矩的方向和激光的极化方向，一个反应坐标会被优先激发，导致化学键的选择性裂解。孔教授的教学计划包括开设一门以“个案研究”为主的化学反应动力学新课程，以及从历史的角度教授现有的量子化学课程。多路径反应的选择性是化学动力学和反应动力学中最令人着迷的问题之一，实现选择性一直是许多科学努力的主要动力。具有选择性，可以分离和详细研究不同的反应途径。这种能力不仅可以更深入地了解每个反应路径，还可以对系统进行调查，否则这些系统将过于复杂而无法解决。

Wei Kong of Oregon State University has been awarded a CAREER grant in the Experimental Physical Chemistry Program to investigate ways of orienting chemical reactants to achieve reaction selectivity. The goal is the ability to selectively cleave a designated chemical bond with minimum effects from competitive pathways. Using supersonic molecular beams and moderate electric fields, orientation of polar reactants has been observed. The oriented chemical bond will then be selectively dissociated by a linearly polarized laser. Depending on the direction of the transition dipole moment of the oriented molecules and the polarization direction of the laser, one reaction coordinate will be preferentially excited, resulting in selective cleavage of a chemical bond. Prof. Kong's educational plans include development of a new course on chemical reaction dynamics emphasizing a `case studies` approach, and the teaching of an existing quantum chemistry course from a historical perspective. Selectivity in a multiple-path reaction is one of the most fascinating questions in chemical kinetics and reaction dynamics, and achieving selectivity has been a major driving force in many scientific endeavors. With selectivity, different reaction pathways can be isolated and investigated in detail. This ability will not only allow a deeper understanding of each reaction path, but also enable investigations of systems that would otherwise be too complicated to tackle.