Photoelectron spectroscopy of f-element complexes

Abstract

Although the chemical bonding of actinide complexes is far from being well understood and , hence, there is a high demand of details of their electronic structure, only few theoretical and/or experimental approaches are capable to probe deep insight into such aspects. Today almost all informations on the bonding have been generally drawn from reactivity data [1] ! In fact, sophisticated MO calculations are hardly practicable with 5f-element complexes because of the very large basis set required while responses of most usual spectroscopic techniques are very hard to be rationalized and/or provide informations only on crystal field aspects. By contrast, gas-phase UV photoelectron spectroscopy is a well established spectroscopic technique which provides: 1. the energy ordering of ‘valence’ MOs. 2. the possible contribution of metal AOs to various MOs by using compared HeI vs. HeII relative intensity variations (this specially applies to spectra of 5f-element complexes). 3. and, finally, an adequate reference to test results of theoretical calculations at any level. This discussion will be mainly limited to investigations carried out at the Chemistry Department of University of Catania on several classes of complexes of f-elements.