A Discussion on photoelectron spectroscopy - Photoelectron spectra of some polyatomic molecules

Abstract

The photoelectron spectra of ethylene, ethylene-d4, ammonia, and ammonia-d3 have been measured using a hemispherical high resolution electrostatic spectrometer and the 584 MATHS SYMBOL helium resonance line as the exciting radiation. Many ionization potentials have been determined for each compound and vibration structure associated with the transitions leading to the various ionization potentials has in many cases been well resolved. It has been possible to suggest reasonable assignments for the corresponding vibrational modes. The photoelectron spectra of MATHS FORMULA obtained using neon radiation (736 and 744 MATHS SYMBOL) shows a progression of twenty-one vibrational transitions, with maxima at v = 1 and v = 7. This is larger than the number of vibrational transitions observed with the 584 MATHS SYMBOL helium line and it is postulated that the extra structure observed arises from ionization processes from a long-lived excited state of oxygen.