Laser Vaporization Generation of Radical Ions and Reactive Intermediates for Matrix Isolation ESR Studies

奈特教授得到了实验基金会的资助。 物理化学研究化学反应产物 在高能量脉冲激光汽化下产生 使用电子自旋共振（ESR）光谱法在条件下测定。 从这些研究中获得的科学知识可以 在包括硅沉积的几个领域中是重要的 微电子制造中涉及的工艺 组分和活性中间体的鉴定 涉及高层大气化学。 这项研究是在 与化学专业的本科生合作， 获得激光、高真空技术、ESR的经验 光谱分析、质谱分析和光谱模拟，所有 其中为从事科学事业提供了良好的准备， 工程. 脉冲激光产生阳离子、阴离子和中性自由基 蒸发，自由基通过飞行时间识别 质谱，并被困在氖矩阵在4 K。 许多新的分子自由基离子正在产生， 在奈特教授的实验室中首次进行了表征。 得到的电子自旋共振谱具有线宽 其可与气相中的那些相比较，并允许 超精细结构和g值的测定。 超精细参数对电子 波函数，因此提供了严格的从头算测试 正在进行的理论计算， 与多个理论团体合作。

Professor Knight is supported by a grant from the Experimental Physical Chemistry Program to study chemical reaction products generated under high energy pulsed laser vaporization conditions using electron spin resonance (ESR) spectroscopy. Scientific knowledge obtained from these studies could be important in several areas including silicon deposition processes involved in the fabrication of microelectronic components and identification of reactive intermediates involved in upper atmospheric chemistry. This research is done in collaboration with undergraduate students in chemistry who gain experience with lasers, high vacuum technology, ESR spectroscopy, mass spectrometry, and spectral simulations, all of which provide good preparation for careers in science and engineering. Cation, anion and neutral radicals are produced by pulsed laser vaporization, the radicals are identified by time-of-flight mass spectroscopy, and are trapped in a neon matrix at 4 K. Many new molecular radical ions are being generated and characterized for the first time in Prof. Knight's laboratory. The electron spin resonance spectra obtained have linewidths which are comparable to those in the gas phase and allow the determination of hyperfine structure as well as g values. Hyperfine parameters are extremely sensitive to the electronic wavefunction and hence provide stringent tests of ab initio theoretical calculations which are being carried out in collaboration with several theoretical groups.