Reaction Dynamics of Metastable Atom with Molecules in Higher Energy Region

用光电子能谱研究亚稳原子与高能区靶分子碰撞的反应动力学一直是本研究的主题。我们发展了新的技术：(1)测量激发态发射截面与碰撞能关系的方法；(2)用液氮冷却的CCD探测器测量发射光谱的高分辨率光谱。利用这些技术测量了产物的发射截面和转动分布。亚稳原子与靶分子的相互作用势及其离解和电离反应动力学如下：1.仅对N_2产生的N_2^+(B-X)体系，研究了亚稳原子与靶分子碰撞产生的物种发射截面的碰撞能量关系。在这项研究中，我们研制了一台由N_2产生的亚稳束源…More可以在120-200 meV范围内改变亚稳态原子的平均动能。虽然束的动能分布比较宽，但这种束源具有很强的通量，可以适用于很多靶分子。在这个项目中，我们阐明了CH3X(X=H，Cl，BrI)，CCl3X(X=H，F，Cl，BrI)，SiCl4，GeCl4与He(2^3s)碰撞的离解和电离动力学。2.为了测量更高分辨率的发射光谱，我们研制了液氮冷却的CCD探测器和光谱仪的组合。该光学探测系统不需要标定亚稳态束流和靶分子在碰撞区域的压强的起伏。通过对探测器每个像素的灵敏度进行校准，该系统可以在比光电倍增管更短的时间内获得良好的S/N比的主题光谱。在这个项目中，我们测量了CO^+(A，B)和N_2^+(B)的转动布居对碰撞能的依赖关系，阐明了CO和N_2的He(2^3s)Penning电离的碰撞动力学。

It has been the subject of this study to clarify reaction dynamics in collisions of metastable atoms with target molecules in higher energy region using photoemission spectroscopy. We have developed new techniques concerning (1) the method measuring the dependence of emission cross sections for excited species on the collision energy and (2) the high resolution spectroscopy of emission spectra by using a liquid nitrogen cooled CCD detector. Emission cross sections and rotational distributions of products have been measured by means of these techniques. The interaction potentials between the metastable atoms and the target molecules and the reaction dynamics of dissociation and ionization have been clarified as follows :1.The collision-energy dependence of the emission cross sections for species produced by the collision of metastable atoms and target molecules were studied only for the N_2^+ (B-X) system produced from N_2. In this study, we have developed a metastable beam source which … More can vary the average kinetic energy of metastable atoms in the 120-200 meV range. Although the kinetic energy distribution of the beam is relatively broad, this beam source has a intense flux, which can apply to a lot of target molecules. In the term of this project, we have clarified the dynamics of dissociation and ionization of CH_3X (X=H,Cl, Br, I), CCl_3X (X=H,F,Cl, Br, I), SiCl_4, GeCl_4 by the collisions with He (2^3S).2.The combination of a liquid nitrogen cooled CCD detector and a spectrometer has been developed in order to measure emission spectra with a higher resolution. This optical detection system does not need to calibrate the fluctuation both the metastable beam flux and the pressure of the target molecule at the collision region. By calibrating the sensitivity for each pixel of the detector, this system can obtain a subject spectrum with a good S/N ratio in a shorter time than that measured using a photomultiplier. In the term of this project, we have measured the dependences of the rotational populations for CO^+ (A,B) and N_2^+ (B) on the collision energy, and have clarified the collision dynamics of the He (2^3S) Penning ionization of CO and N_2. Less