Acta Phys. -Chim. Sin. ›› 2005, Vol. 21 ›› Issue (05): 539-543.doi: 10.3866/PKU.WHXB20050516

• ARTICLE • Previous Articles     Next Articles

Vacuum Ultraviolet Photoionization and Photodissociation of Pentafluoroethane

YANG Bin; HUANG Chao-Qun; YANG Rui; WEI Li-Xia; WANG Jing; WANG Si-Sheng; SHAN Xiao-Bin; QI Fei; ZHANG Yun-Wu; SHENG Liu-Si; WANG Zhen-Ya; HAO Li-Qing; ZHOU Shi-Kang   

  1. National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei   230029;  Laboratory of Environmental Spectroscopy, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei   230031
  • Received:2004-11-19 Revised:2005-01-25 Published:2005-05-15
  • Contact: SHENG Liu-Si E-mail:lssheng@ustc.edu.cn

Abstract: The vacuum ultraviolet photoionization and photodissociation of pentafluoroethane have been studied by using synchrotron radiation. The ionization potential of pentafluoroethane is determined to be (12.25±0.10) eV. Photoionization efficiency (PIE) curves for CF2CF3+、CHFCF3+、CF2CF2+、CF3+、CHF2+、CHF+ and CF+ have been measured. The appearance potentials (AP) of these ions are obtained from their PIE curves, and they are (13.93±0.10) eV, (15.25±0.10) eV, (15.12±0.10) eV, (13.30±0.05) eV, (13.05±0.08) eV, (19.17±0.10) eV and (19.56±0.15) eV, respectively. In addition, the energetics of the dissociative photoionizations have been examined by ab initio Gaussian-3 calculations. The computational results are useful in establishing the dissociation channels near the ionization thresholds. According to the experimental results and the energies calculated by Gaussian-3 theory, the main possible pathways of the photodissociation have been analyzed. And the dissociation energies of the molecule and its cation have been derived from experiment and calculation.

Key words: Pentafluoroethane, Photoionization, Appearance potential, Dissociation energy