Investigation of photophysical processes as the basis for quantitative imaging of gas-phase mixing processes with tracer LIF

这一研究项目的目的是改进对有机示踪剂(对)分子荧光的光物理理解，以及在扩展参数范围(温度、压力、浴气组成)下表征荧光性质，并收集网络数据库(TracerSim)中的扩展数据集。对气相中的混合过程进行时间和空间分辨的定量观测对于优化例如气相合成或燃烧过程非常重要。为此，有机分子经常被用作成像诊断中的荧光示踪剂(示踪剂激光诱导荧光，Tracer-LIF)，以确定感兴趣的定量信息(例如，温度或混合质量)，因为荧光特性对环境条件敏感。在这个研究项目中产生的洞察力随后可以用于通过更好地理解潜在的光物理来改进诊断方法。为此，第二个供资期侧重于以下主题：a)在过去几年中，同时使用两种或两种以上示踪剂对混合物中的几种数量进行联合测定。人们一再指出，对激发分子之间的相互作用的理解不够充分，不能无误差地解释测量的信号强度。现在，这种知识的缺乏将通过描述受控条件下示踪剂-示踪剂相互作用的特征和建模来填补。此外，将使用更多实际相关的示踪剂来验证在第一个资助期内获得的关于自猝灭和激发波长影响的结果，这些结果对示踪剂LIF在实际情况中的应用是重要的。b)在第一个资助期确定的荧光特性以及进一步示踪剂的最新测量数据将被纳入已经部分实施的基于网络的TracerSim数据库。该数据库将得到进一步完善，将有助于收集的光物理数据的可用性，从而将有助于在整个研究界更好地使用TRACE-LIF。c)该项目的新成果将被应用到已建立的光物理荧光量子产率模型中，以提高数据解释能力，并将其适用范围扩大到更多迄今尚未调查的物种。这些模型将被集成到TracerSim网络数据库中进行内插和外推。此外，还将实现对实验示踪剂-LIF数据的分析工具。

The aim of this research project is the improvement of the photophysical understanding of the molecular fluorescence of organic tracer (pairs) as well as the characterization of fluorescence properties in an extended parameter range (temperture, pressure, bath gas composition) and the collection of extended datasets in a web database (TracerSim). Quantitative time- and spatially resolved observation of mixing processes in the gas phase is important for optimizing of, e.g., gas-phase-synthesis or combustion processes. For this purpose, organic molecules are often used as fluorescence tracers in imaging diagnostics (tracer laser-induced fluorescence, tracer-LIF) to determine the quantitative information of interest (e.g., temperature or mixing quality) since fluorescence properties are sensitive to the environmental conditions. The insight generated in this research project can then be used the improvement of diagnostics methods through a better understanding of the underlying photophysics. For this purpose, the second funding period focuses on the following topics:a) In the past years, two or more tracers were used simultaneously for the combined determination of several quantities in mixtures. It has been repeatedly stated that the interaction of the excited molecules is not sufficiently understood to be able to interpret the measured signal intensities without errors. Now, this lack of knowledge will be filled by characterizing and modeling the tracer-tracer interaction under controlled conditions. Furthermore, the results on self-quenching and on the influence of the excitation wavelength gained in the first funding period, which showed to be important for the application of tracer LIF in practical situations will be validated using further practically-relevant tracers.b) The fluorescence properties determined in the first funding period as well as newly measured data for further tracers will be included into the already partially implemented web-based TracerSim database. This database will be further refined and will facilitate the usability of the collected photophysics data and will thus contributes to a better usage of tracer-LIF in the entire research community.c) The new results of this project will be implemented into established photophysical fluorescence quantum yield models to improve the data interpretation capabilities and to extend their applicability to further species, not investigated so far. The models will be integrated into the TracerSim web database for interpolation and extrapolation. Furthermore, an analysis tool for experimental tracer-LIF data will be implemented.