Dynamical Resonances in Chemical Reactions and Chemical Bonding

瓦伦蒂尼博士得到了《物理学》杂志的资助。 化学计划，研究结构和动力学 气相化学反应中的过渡态。 瓦伦蒂尼 开发了一种光谱技术， 对短寿命中间体的间接观察 （过渡态）长期以来一直是理论上 在化学反应中预测但从未观察到。 瓦伦蒂尼博士的研究涉及所谓的 转动激发截面中的Feshbach共振 其被观察用于气相中的化学反应。 直接观察涉及国与国之间的动态， 其中振动和转动量子态（v，j） 反应物通过自由射流膨胀冷却制备， 通过受激拉曼激发探测。 的碰撞能量 反应物是经过选择、变化和精确规定的 通过激光光解双原子前体， 反应物原子。 振动和转动（v '，j'）分析 在单一碰撞条件下的反应产物为 使用共振增强多光子电离来实现。 瓦伦蒂尼博士的研究计划是由他最近的 发现了邻氢、仲氢的Feschbach共振 交换反应 这一观察使他能够推断出 线性三原子跃迁的振动能态 在这个反应中发生的状态。 在这方面的进一步研究 该领域将涉及氢氘交换反应， 氯气与氯化氢的反应， 碘和溴与它们相应的氢的反应 卤化物。 这些物质的相干拉曼光谱将是 获得阐明理论预测的性质 振动键合

Dr. Valentini is supported by a grant fom The Physical Chemistry Program to study the structure and dynamics of transition states in gas phase chemical reactions. Valentini has developed a spectroscopic technique which permits the indirect observation of the short-lived intermediates (transition states) which have long been theoretically predicted but never observed in chemical reactions. Dr. Valentini's research involves the studies of so-called Feshbach resonances in rotational excitation cross sections which are observed for chemical reactions in the gas phase. The direct observations involve state-to-state dynamics in which the vibrational and rotational quantum states (v,j) of the reactants are prepared by free-jet expansion cooling and probed by stimulated Raman excitation. The collision energy of the reactants is selected, varied, and precisely specified through laser photolysis of a diatomic precursor to generate the reactant atom. Vibrational and rotational (v',j') analysis of the reaction products under single collision conditions are effected using resonance-enhanced multiphoton ionizaiton. Dr. Valentini's research program is motivated by his recent discovery of Feschbach resonances in the ortho-, para-hydrogen exchange reaction. This observation permitted him to infer the vibrational energy states of the linear triatomic transition state which occurs in this reaction. Further studies in this area will involve the hydrogen deuterium exchange reaction, the reaction of chlorine with hydrogen chloride, and the reaction of iodine and bromine with their corresponding hydrogen halides. Coherent Raman spectra of these species will be obtained to elucidate the nature of the theoretically predicted vibrational bonding.