High resolution core-level electron spectroscopy on free molecules and atoms

Abstract

Electron spectroscopy on free atoms and molecules using synchrotron radiation from an undulator is outlined. The high brilliance of the synchrotron radiation in combination with high efficiency monochromators and modern high resolution electron spectrometers make it possible to record electron spectra from core levels with a resolution of the order of 10–100 meV, even at high kinetic energies. New aspects of the spectroscopy are discussed, Auger resonant Raman spectra are presented, both in the case of atoms and molecules, and also angular resolved results at sub-natural resolution are reviewed. Particular attention is paid to the dissociation of core excited molecules in connection with resonant Auger decay. Vibrational resolution in core photoelectron spectra is also discussed using propene as an example, and the relevance of high precision chemical binding energy shifts is discussed.