HR-XAS and variable photon energy photoelectron studies of heavy metal compounds in vapour phase

Metal Compounds (MC) have been extensively investigated by Synchrotron Radiation (SR) spectroscopy (XAS and PES) in the solid state due to the fundamental importance of these materials in catalisys, sensors and a range of other applications. On the other hand SR spectroscopy of free MCs in the gas phase is a barely touched subject. This is certainly due to additional experimental difficulties in dealing with not stable, often not volatile and rather aggressive compounds, which are however routinely manipulated in chemistry laboratories. On the other hand we have to stress that the interest in SR photoemission and absorption of MCs in gas phase is twofold: 1) we expect to observe the full phenomenology exhibited in the solid state, with the great advantage offered by the much higher resolution available in gas phase and the absence of complications associated with solid state effects. 2) we expect that precise new spectral data will lead to parallel development in theoretical models. A few aspects are for example: the involvement of d or even f orbitals in the bonding, many body effects, precise calculation of oscillator strengths for metals and ligands. In this framework we realised a wide range of experiments, starting from resonat photemission and High Resolution - XAS study of metal halides, to variable energy photoemission studies of transition metal halides and oxides (TiCl4, VOCl3, CrO2Cl2, ReO3Me) and transition metal's and rare earth's borohydrides [X(BH4)4, X = Hf, Zr, U]. We want to shows some of the most interesting results we obtained and to stress the need of a third generation synchrotron radiation source to access the optimum photon energy for each cross section feature in this class of materials.