Detection and reaction kinetics of reactive species in particle-forming environments using IR modulation spectroscopy by the example of dusty plasmas

该项目旨在开发和测试高灵敏度的吸收光谱调制技术，用于对颗粒形成环境中的瞬时物种进行时间分辨检测。测量将在红外(IR)光谱范围内进行，从而实现对多种气相物种的定量检测。本文着重研究了甲烷和乙炔等离子体中小分子烃自由基CH3、C2H和C2H3的光谱和化学动力学。一般而言，通过监测正在进行的颗粒形成过程中的气相物质的浓度分布(在等离子体、火焰中、在大气气溶胶中)，新的探测系统将有可能得出关于表面反应及其对整个气相化学的反馈的作用的结论。通过这种方式，可以更容易地识别由反应表面或等离子体中的特殊条件所介导的新的反应路径。

The project aims at the development and testing of highly sensitive absorption spectroscopic modulation techniques for time-resolved detection of transient species in particle forming environments. Measurements will be performed in the infrared (IR) spectral range, hence enabling the quantitative detection of multiple gas phase species. Here, a focus is set on the investigation of the spectroscopy and chemical kinetics of the small hydrocarbon radicals CH3, C2H und C2H3 in dusty methane and acetylene plasmas. In general, by monitoring the concentration profiles of gas phase species during ongoing particle formation processes (in plasmas, in flames, in atmospheric aerosols), the new detection system will make it possible to draw conclusions about the role of surface reactions and their feedbacks on the overall gas phase chemistry. In this way, new reaction pathways that are mediated by the reactive surfaces or the special conditions in a plasma can be more easily identified.