Transition Metal Chemistry in Crossed Molecular Beams

H.康奈尔大学的弗洛伊德戴维斯得到实验物理化学计划的支持，使用交叉分子束在明确定义的条件下对过渡金属原子的双分子反应进行详细的实验研究。 研究将集中于涉及基态电子态以及通过激光激发制备的过渡金属原子的亚稳态电子激发态的反应。 化学反应产物和非反应性散射的过渡金属原子将使用电子碰撞，真空紫外光电离或1+1共振增强多光子电离（REMPI）进行检测。 这些产品的角和速度分布将作为碰撞能量的函数进行测量，以深入了解反应机制和多余的能量处置到产品的自由度。 将确定C-H插入等关键过程的潜在能垒。 这些实验的结果将有助于直接测试过渡金属量子化学领域的最先进的从头计算。过渡金属中心在通常不反应的共价键中引发化学变化的能力在均相和多相催化以及有机和/或有机金属化学中具有重要意义。 控制中性金属插入各种有机键的潜在因素仍然知之甚少，尽管有兴趣实现这一知识。 本研究旨在进一步了解过渡金属化合物与小分子碳氢化合物之间的物理和化学相互作用。 这些结果将为与理论的比较提供实验信息。

H. Floyd Davis of Cornell University is supported by the Experimental Physical Chemistry Program to perform detailed experimental studies of the bimolecular reactions of transition metal atoms under well-defined conditions using crossed molecular beams. Studies will focus on reactions that involve ground electronic states as well as metastable electronically excited states of transition metal atoms prepared by laser excitation. Chemical reaction products and nonreactively scattered transition metal atoms will be detected using electronic impact, vacuum ultraviolet photoionization, or 1+1 resonance enhanced multiphoton ionization (REMPI). Angular and velocity distributions of these products will be measured as a function of collision energies to gain insights into the reaction mechanisms and excess energy disposal into product degrees of freedom. Potential energy barriers for key processes such as C-H insertion will be determined. Results from these experiments will facilitate direct tests of state of the art ab initio calculations in the field of transition metal quantum chemistry. The ability of transition metal centers to initiate chemical change in normally unreactive covalent bonds is of major importance in homogeneous and heterogeneous catalysis, as well as in organic and or organometallic chemistry. The underlying factors controlling the insertion of neutral metals into various organic bonds remain poorly understood despite interest in achieving this knowledge. The present studies aim to further comprehension of physical and chemical interactions between transition metal compounds and smaller hydrocarbon molecules. The outcomes will provide experimental information for useful comparison with theory.