• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Radical-molecule reaction dynamics studied using a pulsed supersonic Laval nozzle flow reactor between 53 and 188 Kelvin.
【24h】

Radical-molecule reaction dynamics studied using a pulsed supersonic Laval nozzle flow reactor between 53 and 188 Kelvin.

机译：自由基-分子反应动力学的研究是使用脉冲超音速拉瓦尔喷嘴流动反应器在53和188开尔文之间进行的。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

A pulsed supersonic Laval nozzle flow reactor has been employed to investigate a variety of neutral-radical reaction processes at temperatures between 53 and 188 Kelvin. These supersonic flows simulate the conditions found in the Earth's upper atmosphere as well as certain environments in the interstellar medium and outer planetary atmospheres and thus provide direct information on the chemistry and physical processes occurring in those environments. Studies of this type, in the limit of 0 Kelvin, coupled with modern astronomical observations of planetary atmospheres and dense molecular clouds provide for a global understanding of chemistry in cold environments. With this in mind, the flow reactor was used to conduct fundamental studies involving the reactivity of hydroxyl (OH) and imidogen (NH) radical species with a variety of partners.; More specifically, the reactions of OH+HBr and all of the H/D isotopic variants were explored between 53 and 135 K, with the goal of elucidating the kinetic isotope effects, both primary and secondary, for a reaction system occurring over a potential energy surface without an appreciable barrier, that demonstrates inverse temperature dependence. While not of direct astronomical importance, the reaction of OH+HBr does affect the partitioning of Br in the Earth's atmosphere, and knowledge of kinetic isotope effects helps one understand the chemistry leading to H/D fractionation observed in a variety of interstellar environments.; The reactions of NH radical with NO, saturated, and unsaturated hydrocarbons were also studied between 53 and 188 Kelvin in the Laval nozzle flow reactor. These species were chosen as most are important constituents in the atmosphere of Titan, which is known to possess a rich organic chemistry. The reactions of NH with the unsaturated hydrocarbons are found to display negative temperature dependence over the window investigated, and are thought to proceed through an addition mechanism.; Finally, the flow reactor was also coupled to a tunable vacuum and extreme ultraviolet frequency source based on four wave frequency mixing to allow for studies of radical species with their first electronic transitions in this frequency range. A discussion of the development, implementation, and future directions is included.
机译：脉冲超音速拉瓦尔喷嘴流动反应器已用于研究温度在53至188开氏温度之间的各种中性自由基反应过程。这些超音速流模拟了在地球高层大气以及星际中层和外层行星大气中某些环境中发现的条件，因此提供了在这些环境中发生的化学和物理过程的直接信息。此类研究的极限温度为0开尔文，加上对行星大气层和稠密分子云的现代天文观测，为全球了解寒冷环境中的化学反应提供了条件。考虑到这一点，流动反应器被用于进行基础研究，涉及羟基（OH）和亚胺基（NH）自由基与各​​种配偶的反应。更具体地说，在53 K和135 K之间探索了OH + HBr和所有H / D同位素变体的反应，目的是阐明在势能范围内发生的反应系统的动力学同位素效应，包括一次和二次动力学同位素效应表面没有明显的阻挡层，表明存在反温度依赖性。 OH + HBr的反应虽然不具有直接的天文重要性，但确实会影响Br在地球大气中的分配，并且了解动态同位素效应有助于人们理解在多种星际环境中导致H / D分级的化学反应。在拉瓦尔喷嘴流动反应器中，还研究了NH自由基与NO，饱和烃和不饱和烃的反应，反应温度为53至188开尔文。选择这些物种是因为Titan大气中最重要的成分，Titan大气中拥有丰富的有机化学成分。发现NH与不饱和烃的反应在所研究的窗口上显示出负的温度依赖性，并认为是通过加成机理进行的。最后，该流动反应器还与基于四波混频的可调真空和极紫外频率源耦合，以便研究具有该频率范围内第一个电子跃迁的自由基物种。包括对开发，实施和未来方向的讨论。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号