The application of a quasi-CW (80 MHz, picosecond pulsed), tunable Ti:sapphire laser to absorption detection of transient species in a flash photolysis kinetics experiment is presented. This work reports measurements of first-order rate constants for the reaction of vinyl radical with various alkenes: ethylene, propene, isobutene, 1-butene, and 2-butene, performed over a temperature range of 300 K to 700 K at 100 torr. Vinyl radicals (H2C=CH) were generated by laser photolysis of vinyl iodide (C2H3I) at 266 nm and time-resolved absorption spectroscopy was used to probe vinyl radicals through the various absorption lines including: 404, 423.2, 445, and 475 nm. We report the self-reaction rate of vinyl radical. Second order chemical reactions require an accurate determination of the initial radical concentration, which we determined using direct laser absorption by I atom at 1315 nm. The time-resolved vinyl radical concentration is fitted to a second order kinetic equation to extract the self-reaction rate constant. The current study finds the self-reaction rate to be more than a factor of two slower than previous studies.
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机译：准CW的应用（80兆赫，皮秒脉冲的），可调谐的Ti：蓝宝石激光器，以在闪光光解动力学实验瞬态物种的吸收检测被呈现。乙烯，丙烯，异丁烯，1-丁烯和2-丁烯，在100乇进行的温度范围内300°K至700 K：一级速率常数的乙烯基基团与各种烯烃的反应该工作报告测量结果。乙烯基的基团（H 2 C = CH）通过碘乙烯（C2H3I）的激光光解在266纳米产生和时间分辨吸收光谱是通过各种吸收线，包括用于探测乙烯基的基团：404，423.2，445，和475纳米。我们报告的乙烯基激进的自我反应速度。二阶的化学反应所需要的初始自由基浓度，我们确定在1315处使用直接激光吸收由I原子的精确确定。时间分辨乙烯基自由基浓度被装配到第二级动力学方程来提取自反应速率常数。目前的研究发现自我反应速度要超过两个比以往的研究更慢的一个因素。
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