Enhancement of the Undergraduate Physical Chemistry Laboratory: A Versatile and Novel Pulsed Laser-Based System for Nanosecond Time-Resolved Luminescence Studies in Molecular Phot

本科生物理化学实验室的增强：用于分子光纳秒时间分辨发光研究的多功能新型脉冲激光系统

• 批准号: 9952604
• 负责人: Ramaswami Viswanathan
• 金额: $ 3.57万
• 依托单位: Beloit College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-03-01 至 2003-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9952604&HistoricalAwards=false
• 关键词: Enhancement; Undergraduate; Physical; Chemistry; Laboratory

Chemistry (12) Ultrashort laser pulse-based experiments have become ubiquitous in experimental physical chemistry. In order for students to understand recent developments and obtain "hands on" experience with such techniques, access to a pulsed laser-based system with pump-probe capability for luminescence studies is important. In this project, the instrumentation to do this is being incorporated into the undergraduate physical chemistry laboratory curriculum. The system consists of a Q-Switched YAG laser with harmonic generation in either the near-UV (355 nm) or mid-UV (266 nm) with a 3 ns (4-8 mJ) pulse, thus providing excitation in a variety of molecules. The fast luminescence is detected by a sensitive PIN photodiode detector with 400 ps response and digitized by an ultrahigh bandwidth (1 GHz) digital oscilloscope. The YAG laser is also used to pump an existing tunable dye laser, whose probe output is temporally delayed from 0 to 50 ns using an inexpensive and novel optical delay line based on a toy train track and engine. A set of experiments for the undergraduate physical chemistry laboratory that measure fluorescence lifetimes of a series of aromatic hydrocarbons and also directly monitor intersystem crossing processes on the nanosecond time scale using optically delayed triplet- triplet absorption are being adapted and implemented, with enhancements. The adapted materials come from both the chemical education literature (J. Chemical Education) and from the research literature. The laser equipment is also being introduced into inorganic, organic and advanced organic courses, courses not normally associated with laser chemistry. This considerably broadens the impact of this project. Evaluation and assessment activities are being assisted by an external evaluator, experienced in laser chemistry, and by a chemical education specialist. The results will be disseminated through dedicated Web pages and papers submitted to the Journal of Chemical Education.

化学（12）基于超短激光脉冲的实验在实验物理化学中已经无处不在。为了让学生了解最新的发展，并获得这些技术的“动手”经验，使用具有泵浦探测能力的脉冲激光系统进行发光研究非常重要。在本项目中，为此所使用的仪器被纳入了本科物理化学实验课程。该系统由一个调q YAG激光器组成，在近紫外（355nm）或中紫外（266nm）产生谐波，脉冲为3ns (4-8 mJ)，从而在各种分子中提供激发。快速发光由灵敏的PIN光电二极管检测器检测，响应速度为400ps，并通过超高带宽（1ghz）数字示波器进行数字化。YAG激光器也用于泵浦现有的可调谐染料激光器，其探头输出暂时延迟从0到50纳秒，使用廉价和新颖的光学延迟线，基于玩具火车轨道和发动机。一套用于本科物理化学实验室的实验，测量一系列芳烃的荧光寿命，并利用光学延迟三重态-三重态吸收在纳秒时间尺度上直接监测系统间的交叉过程，正在调整和实施，并进行了改进。改编材料来自化学教育文献（J. chemical education）和研究文献。激光设备也被引入到无机、有机和高级有机课程中，这些课程通常与激光化学无关。这大大扩大了这个项目的影响。评价和评价活动由一名在激光化学方面有经验的外部评价人员和一名化学教育专家协助进行。研究结果将通过专门的网页和提交给《化学教育杂志》的论文进行传播。