Photo-absorption cross sections have been measured for methyl iodide, CF3I (310nm>λ>110nm) and dichlorodifluoromethane, CCl2F2 (225nm>λ>110nm) using synchrotron radiation. Electron energy loss spectroscopy was also used to probe the electronic and vibronic excitation of CF3I. Electronic states have been assigned to each of the observed absorption bands incorporating both valence and Rydberg transitions. The measured VUV cross sections are used to derive the photolysis rates in the terrestrial atmosphere and hence determine the potential importance of each gas in global warming and ozone depletion.
- Electron energy loss spectroscopy (EELS)
- VUV photo-absorption
- Synchrotron radiation
- Plasma etching
- Photolysis rates