Thorin Emil, Schmidt Florian M
Opt Lett. 2020 Sep 15;45(18):5230-5233. doi: 10.1364/OL.400614.
Photofragmentation spectroscopy is combined with tunable diode laser absorption spectroscopy to measure the line shape of the fragment species. This provides flexibility in choosing the UV pulse location within the line shape and accurate quantification of both target species and background fragment concentrations, even under optically thick conditions. The technique is demonstrated by detection of potassium hydroxide (KOH) and atomic potassium K(g) above solid KOH converted in a premixed methane-air flat flame. Time series of KOH(g) and K(g) concentrations are recorded as a function of solid KOH mass and flame stoichiometry. The total substance released during the conversion is in good agreement with the initial solid KOH mass. Under fuel-rich conditions, increased K(g) concentrations at the expense of KOH(g) are observed compared to thermodynamic equilibrium.
光解离光谱法与可调谐二极管激光吸收光谱法相结合，用于测量碎片物种的线形。这在选择线形内紫外脉冲位置方面提供了灵活性，并且即使在光学厚条件下，也能对目标物种和背景碎片浓度进行准确量化。通过检测预混甲烷 - 空气平面火焰中转化后的固体氢氧化钾（KOH）上方的氢氧化钾（KOH）和钾原子K（g），证明了该技术。记录了KOH（g）和K（g）浓度的时间序列，作为固体KOH质量和火焰化学计量比的函数。转化过程中释放的总物质与初始固体KOH质量高度吻合。与热力学平衡相比，在富燃料条件下，观察到以KOH（g）为代价的K（g）浓度增加。
