Studying of Ar Cluster Ionization Levels by X-Ray Laser Photoelectron Spectroscopy

• Main Authors: Shih-Jie Wong, 翁士傑
• Other Authors: Hsu-hsin Chu
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/p8b6uh

碩士 === 國立中央大學 === 物理研究所 === 96 === Cluster plays an important role in chemical reaction and catalysis. Many physical and chemical phenomenon of surface are the dynamics of clusters. The purpose of this thesis is to study the relations between cluster size and ionization potential by x-ray photoelectron spectroscopy, XPS. We use an x-ray laser pulse which is produced from krypton as the source for ionizing clusters. The wavelength of x-ray laser pulse is 32.8 nm. The polarization is random polarized. In the meantime, we build time-of-flight spectrometer as a tool for measuring energy spectrum of x-ray photoelectrons. Furthermore, we use magnetic bottle device to increase the collection efficiency of photoelectron. According to our estimation, the solid angle for detecting electrons is about 2π. The experimental results show that the magnetic bottle does improve the collection efficiency. We control the size of argon cluster by changing the backing pressure of cluster jet. Then we study the relations between the cluster size and ionization potential of argon cluster. The results show that the ionization potential decreases as the cluster size increases. The experimental results agree with other group’s studying. This is due to polarization screening. By the results of the experiment, we can improve the design of experiment to get better resolution and accuracy in using XPS. We expect the technique will apply to more widely research.