Bodi Andras, Johnson Melanie, Gerber Thomas, Gengeliczki Zsolt, Sztáray Bálint, Baer Tomas
Paul Scherrer Institut, Villigen 5232, Switzerland.
Rev Sci Instrum. 2009 Mar;80(3):034101. doi: 10.1063/1.3082016.
An imaging photoelectron photoion coincidence spectrometer at the vacuum ultraviolet (VUV) beamline of the Swiss Light Source is presented and a few initial measurements are reported. Monochromatic synchrotron VUV radiation ionizes the cooled or thermal gas-phase sample. Photoelectrons are velocity focused, with better than 1 meV resolution for threshold electrons, and also act as start signal for the ion time-of-flight analysis. The ions are accelerated in a relatively low, 40-80 V cm(-1) field, which enables the direct measurement of rate constants in the 10(3)-10(7) s(-1) range. All electron and ion events are recorded in a triggerless multiple-start/multiple-stop setup, which makes it possible to carry out coincidence experiments at >100 kHz event frequencies. As examples, the threshold photoelectron spectrum of the argon dimer and the breakdown diagrams for hydrogen atom loss in room temperature methane and the chlorine atom loss in cold chlorobenzene are shown and discussed.
介绍了瑞士光源真空紫外（VUV）光束线上的成像光电子光离子符合光谱仪，并报告了一些初步测量结果。单色同步辐射VUV辐射使冷却的或热的气相样品发生电离。光电子被速度聚焦，对于阈值电子具有优于1 meV的分辨率，并且还用作离子飞行时间分析的起始信号。离子在相对较低的40 - 80 V cm⁻¹场中加速，这使得能够直接测量10³ - 10⁷ s⁻¹范围内的速率常数。所有电子和离子事件都在无触发多起始/多停止设置中记录，这使得能够在>100 kHz的事件频率下进行符合实验。作为示例，展示并讨论了氩二聚体的阈值光电子能谱以及室温甲烷中氢原子损失和冷氯苯中氯原子损失的分解图。
