RUI: Closing the Gap Between Hot and Cold Collisions--Orientation, Alignment, and Velocity Effects on Associative Ionization of State-selected Atoms in a Single Beam

本研究项目以研究分子结构和探索碰撞理论为目的，测量激发态原子之间的碰撞。主要目标是弥合传统碰撞研究（在热，即，在气室中的温暖温度）和在超冷阱中进行的实验。实验过程利用窄带宽二极管激光器选择薄的热铯束的速度分量。精确控制的速度分量之间的碰撞导致缔合电离，其中两个激发的原子通过喷射电子以带走多余的能量而形成分子键。窄带宽二极管激光器还允许控制原子取向和排列，这是碰撞理论中的重要参数。 对于铯的情况，缔合电离提供了一个简单但重要的化学键形成的例子，涉及单电子键。 这种简单性使得铯的缔合电离成为碰撞理论的一个很好的检验。除了评估理论和理解亚开尔文环境中的碰撞过程外，该项目的更广泛影响还包括加强拉斐特学院的研究和教学基础设施，并培养未来的物理学家，以便进入研究生院和在工业中就业。本科生通过直接参与这项研究提供了实际的动手实验室经验。该项目的各个方面到本科实验室课程的整合提供了第二条途径，通过它学生接触到现代实验室技术。

This RUI research project will measure collisions between excited-state atoms with the purpose of studying molecular structure and exploring collision theory. The primary goal is to bridge the velocity gap between traditional collision studies (done at thermal, i.e., warm temperatures in gas cells) and experiments carried out in ultracold traps. The experimental procedure makes use of narrow-bandwidth diode lasers to select thin velocity components of a thermal cesium beam. Collisions between precisely controlled velocity components lead to associative ionization, where two excited atoms form a molecular bond by ejecting an electron to carry off excess energy. The narrow-bandwidth diode lasers also allow control of atomic orientation and alignment, which are important parameters in collision theory. For the case of cesium, associative ionization offers a simple, but important example of chemical bond formation, involving one-electron bonds. This simplicity makes associative ionization of cesium a good test of collision theory. Beyond evaluating theories and understanding collision processes in sub-Kelvin environments, the broader impact of this project includes enhancing the research and teaching infrastructure of Lafayette College and training future physicists destined for graduate school and employment in industry. Undergraduates are provided with practical hands-on laboratory experience by participating directly in this research. The integration of various aspects of this project into the undergraduate laboratory curriculum provides a second avenue through which students are exposed to modern laboratory techniques.