H-atom Dissociation Channels in Ultraviolet Photochemistry of m-Pyridyl Radical  

间-吡啶基紫外光化学中的氢原子解离通道

作　　者：Michael Lucas Jasmine Minor 张劲松[1,3] Christopher Brazier 

机构地区：[1]美国加州大学河滨分校化学系,河滨92521 [2]美国加州州立大学长滩分校化学和生物化学系,长滩90840 [3]美国加州大学河滨分校空气污染研究中心,河滨92521

出　　处：《Chinese Journal of Chemical Physics》2014年第6期621-627,I0003,共8页化学物理学报（英文）

基　　金：This work was supported by the US National Science Foundation （CHE-1214157）. Jasmine Minor acknowledges the support from the UC Riverside HSI-STEM Summer Bridge to Research Program and the Summer Research in Science and Engineering [RISE] Program.

摘　　要：The H atom production channels in the ultraviolet （UV） photochemistry of m-pyridyl radical （m-C5H4N） were investigated at excitation wavelengths from 224 nm to 248 nm by high-n Rydberg atom time-of-flight （HRTOF） technique. The photofragment yield （PFY） spectrum of the H atoms indicates a broad UV absorption feature near 234 nm. The product kinetic energy release is small; the average product kinetic energy at the wavelengths from 224 nm to 248 nm is 0.12 to 0.19 of the maximum excess energy （assuming the lowest energy product channel, H＋cyanovinylacetylene）. The product kinetic energy distributions are consistent with the H cyanovinylacetylene, H 3,4-pyridyne, and H 2,3-pyridyne product channels, with H cyanovinylacetylene as the main H-loss channel. The angular distributions of the H-atom products are isotropic. After the UV electronic excitation, the m-pyridyl radical undergoes internal conversion to the ground electronic state and then unimolecular dissoci-ation to the H cyanovinylacetylene, H 3,4-pyridyne, and H 2,3-pyridyne products. The dissociation mechanism of the m-pyridyl radical is similar to that of the o-pyridyl radical reported in the early study.

关 键 词：PHOTOLYSIS Photofragment PYRIDYL PYRIDINE Decomposition Excited state 

分 类 号：O[理学]