Fundamental investigations on the influence of high effective ion temperatures on the kinetics of ion-molecule reactions in the gas phase using high kinetic energy ion mobility spectrometry with selective ion sources

该延续项目的目标是：a）在实验研究的基础上，详细描述气相中离子-分子反应动力学随有效离子温度的变化; B）开发所需仪器，其形式为具有选择性离子源的高动能离子迁移谱仪（HiKE-IMS）。虽然在室温下有大量的数据来描述各种气相反应的动力学，但在更高温度下只有很少的数据。特别是对团簇缔合和解离反应动力学的实验研究几乎是不可用的。众所周知，离子温度的升高影响离子和中性气体分子之间的内能态和相互作用能，从而影响解离和碎裂过程以及气相反应的转化率。在这一延续的范围内，这些影响发生在离子温度升高将从根本上进行调查。该过程的动力学和动态模拟，以及实验数据，最终将提供新的见解的温度依赖性的气相反应动力学，这不仅是学术兴趣，而且还允许特定应用优化的HiKE-IMS的敏感性和选择性检测某些目标化合物。然而，这样的实验研究要求除了目标反应系统之外，在HiKE-IMS中不存在其他反应性离子，因为并行反应使得难以或不可能清楚地解释测量结果。上一个项目的HiKE-IMS尚未满足这一要求，这主要是由于使用了电晕放电源。在延续的范围内，将实现与HiKE-IMS兼容的空心阴极离子源，以生成定义的离子群。此外，激光电离源计划通过共振多光子激发电离分子。特别是，中等极性到非极性的芳香族物质可以非常有选择性地电离，可调谐激光器可以用于研究其他物质类别。此外，可以在空间上和时间上非常限定的范围内产生离子，以便通过独立于其他参数改变电离位置来改变离子在反应区域中的停留时间。这种时间变化使得能够计算反应速率和反应速率常数。为此目的，HiKE-IMS将通过激光束到反应区域中的局部可变耦合来实现。

The objectives of this continuation project are a) a detailed description of the kinetics of ion-molecule reactions in the gas phase as a function of the effective ion temperature on the basis of experimental investigations and b) the development of the required instrumentation in the form of a high kinetic energy ion mobility spectrometer (HiKE-IMS) with selective ion sources. While extensive data are available for room temperature to describe the kinetics of various gas phase reactions, only very few data are available for higher temperatures. Especially, experimental investigations on the kinetics of cluster association and dissociation reactions are hardly available. It is generally known that an increase in ion temperature influences the internal energy states and interaction energies between ions and neutral gas molecules and thus dissociation and fragmentation processes and the conversion rates of gas phase reactions. Within the scope of this continuation, these effects occurring at elevated ion temperatures will be fundamentally investigated. Kinetic and dynamic simulations of the processes, together with the experimental data, will finally provide new insights into the temperature-dependent kinetics of gas phase reactions, which are not only of academic interest, but also allow an application-specific optimization of the HiKE-IMS for sensitive and selective detection of certain target compounds. However, such experimental investigations require that no other reactive ions apart from the target reaction system are present in the HiKE-IMS, since parallel reactions make a clear interpretation of the measurement results difficult or impossible. The HiKE-IMS from the previous project does not yet fulfil this requirement, which is mainly due to the corona discharge source used. Within the scope of the continuation, a hollow cathode ion source compatible with the HiKE-IMS will be realized instead in order to generate defined ion populations. In addition, a laser ionization source is planned for ionizing molecules via resonant multiphoton excitation. In particular, medium polar to non-polar aromatic substances can be ionized very selectively, and tunable lasers can be used to investigate other substance classes. In addition, ions can be generated in a spatially and temporally very defined range in order to vary the residence time of the ions in the reaction region by varying the ionization site independently of other parameters. This time variation enables the calculation of reaction rates and reaction rate constants. For this purpose, a HiKE-IMS will be realized with locally variable coupling of the laser beam into the reaction region.