Spectroscopy and Chemistry of Jet-Cooled Free Radicals

喷射冷却自由基的光谱学和化学

• 批准号: 8806914
• 负责人: G Ellison
• 金额: $ 6万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-07-01 至 1989-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8806914&HistoricalAwards=false
• 关键词: Spectroscopy; Chemistry; Jet; Cooled; Free

This grant in the Organic and Macromolecular Chemistry Program supports research of Dr. G. Barney Ellison, University of Colorado, to study the infrared absorption spectroscopy of jet-cooled organic radicals. The reactions of radicals with ions will also be studied in a fast flow reactor. Radicals are unstable reactive intermediates which are of paramount importance in many combustion processes and high temperature plasmas; spectroscopic probes are needed to monitor the fate of these metastable species. The enterprise is to develop an experiment which will enable preparation of intense radical beams via a free jet expansion. Radicals such as methyl, allyl, and cyanomethyl will be prepared by a variety of photochemical and thermal sources. Sources will be monitored by a photoionization mass spectrometer. Radical densities on the order of 1 mTorr will be prepared and these reactive species will be cooled by the jet to rotational temperatures of about 20 K. These radicals will be investigated by infrared absorption spectroscopy with an FTIR. Selected for study are the family of methyl radicals: methyl, fluoromethyl, difluoromethyl, trifluoromethyl, and cyanomethyl. In all cases, it is planned to establish the molecular geometries and vibrational frequencies. The allyl radical is of similar interest since it is the simplest conjugated hydrocarbon. Clean, characterized radical beams will be used to study the reactions between negative ions, such as hydroxide ion or methoxide ion, and hydrocarbon radicals such as allyl or benzyl. Dr. Ellison hopes to establish the gas phase acidity of allyl to contrast with propene or toluene. Separate experiments will use these radical sources to study the scattering of methyl radicals off clean gold or graphite surfaces. This will establish the sticking coefficients of these radicals as well as the rate of molecular deposition.

有机和高分子化学项目的资助 支持G博士的研究。Barney Ellison，University of 科罗拉多，研究红外吸收光谱的 喷射冷却的有机自由基 自由基与 还将在快速流动反应堆中研究离子。 基是 不稳定的活性中间体， 在许多燃烧过程和高温下的重要性 等离子体;光谱探针需要监测的命运 这些亚稳态物种。 企业号要进行一项实验 通过自由射流膨胀制备强自由基束。 自由基如甲基、烯丙基和氰基甲基将被取代。 通过各种光化学和热源制备。 源将由光电离质量监测 光谱仪 1毫托量级的自由基密度将 这些反应性物质将被冷却， 喷射到约20 K的旋转温度。 这些基团 将通过红外吸收光谱法进行研究， 傅里叶变换红外光谱仪选择研究的是甲基自由基家族： 甲基、氟甲基、二氟甲基、三氟甲基，和 氰甲基。在所有情况下，计划建立 分子几何形状和振动频率。 烯丙基 根式也有类似的意义，因为它是最简单的 共轭烃 干净的，特征化的自由基光束将被用来研究 负离子之间的反应，如氢氧根离子或 甲氧基离子和烃基如烯丙基或 苄基。 埃里森博士希望建立气相酸度 与丙烯或甲苯形成对比。 单独的实验将使用这些激进的来源来研究 甲基自由基从干净的金或石墨上的散射 表面。 这将确定的粘附系数 这些自由基以及分子沉积的速率。