Deexcitation Electron Spectroscopy: A Probe for the Localisation of Valence Wavefunctions in Free and Adsorbed Molecules

Abstract

Deexcitation electron spectroscopy (DES) is the measurement of the kinetic energy distribution of electrons emitted in the decay of highly excited states of molecules formed by core to bound resonant photon absorption. This spectroscopy has the potential of becoming a new probe of the localised properties of the valence electronic states in molecules as well as furnishing new insights into the dynamics of the electronic decay and screening processes. This paper describes the basic principles of DES by following the evolution of the DES spectra in CO, from the isolated CO molecule in the gas phase, through the transition metal carbonyls, to CO adsorbed on a surface. In all three cases the energetics, intensities and dynamics of DES will be compared with photoelectron spectroscopy (PES) and Auger electron spectroscopy (AES).