Spectroscopy and dynamics on electron-ion recombination

气体、液体和固体中的电离现象通常由电子抛射开始，由产生的等离子体粒子（如电子和离子）的碰撞维持，并以电荷清除反应结束，即正离子与负离子之间的复合或正离子与热化电子之间的复合。随着压力的增加，各种应用如等离子体显示面板或大气臭氧发生器的发展，电子-离子复合转变为电子和簇离子。本研究的目的是发展一种新的光谱技术，并从重组中临时产生的超激发分子团簇动力学的角度来证实该阶段的动力学和动力学。为了实现目前的目的，我们在高真空条件下，建立了一种新的质量选择簇离子与单能电子的合并束碰撞装置。该装置由1)簇束离子束源，2)飞行时间质量选择器和3)摆线电子能谱仪组成。在束离子束源中，束离子是由中性团簇在脉冲气体喷嘴中进行超声速膨胀时的电子冲击电离产生的，并由脉冲电场提取。这样提取的簇离子束被加速约5千伏，并通过一个1.2米的漂移管，并使用飞行时间技术进行批量选择。我们已经确认了Ar_<30>和（CO_22）_<30>的质量选择簇离子束。采用融合束技术，用单能量电子束对大量选择的簇离子束进行碰撞；单能电子束的轨迹在摆线谱仪中与质量选择簇束离子束合并，碰撞后与离子束分离。利用电子在垂直于电子束的电场和磁场下的摆线运动原理，同时进行电子的能量色散和轨迹控制。单能电子束的典型能量宽度为80兆电子伏。通过得到Ar和CO_2的散射截面，对摆线电子能谱仪的性能进行了测试，结果与已发表的结果相吻合。所构建的电子-簇离子复合装置对合并束复合实验进行了优化。少

Ionization phenomena in gases, liquids, and solids are generally initiated by the electron ejection, main-tained by the collisions of generated plasma particles, such as electrons and ions, and terminated by the charge clearing reaction, namely, recombination between positive and negative ions or that between positive ions and thermalized electrons. With the increase of pressure, where various applications, such as plasma display panel or atmospheric ozonizer, are developed, the electron-ion recombination changes into the for electrons and cluster ions. The purpose of the present investigation is to develop a new spectroscopic tech-que and to substantiate the dynamics and kinetics of the entitled process in such a phase from a point of view of the dynamics of superexcited molecular clusters temporally generated in recombination.In order to realize the present purpose, we have built a new apparatus for the merged-beams collision of mass selected cluster ions with mono-energetic electron … More s under the high vacuum condition. The apparatus consists of 1) cluster-ion beam source, 2) time-of-flight mass selector, and 3) trochoidal electron spectrometer. In the cluster-ion beam source, the cluster ions are generated by electron impact ionization of neutral clusters in supersonic expansion from a pulsed gas nozzle and extracted by a pulsed electric field. The cluster-ion beam thus extracted is accelerated by about 5 kV and travels through a 1.2 m drift tube and mass-selected using a time-of-flight technique. We have confirmed mass-selected cluster-ion beams up to Ar_<30> and (CO_22)_<30>. The mass-selected cluster ion beam is collided by a mono-energetic electron beam using a merged beams technique ; the trajectory of mono-energetic electron beam is merged with the mass-selected cluster-ion beam in the trochoidal spectrometer, and estranged from the ion beam after the collision. The energy dispersion of electrons and the control of trajectories are simultaneously carried out with the principle of trochoidal electron motion under an electric and magnetic fields both perpendicular to the electron beam. The typical energy width of mono-energetic electron beam is 80 meV.The performance of the trochoidal electron spectrometer is tested by obtaining the scattering cross sections for Ar and CO_2, which reasonably reproduce the published results. The apparatus for the electron-cluster ion recombination thus constructed is optimized for merged-beams recombination experiments. Less