Ionization and photofragmentation of Ru3(CO)12 and Os3(CO)12.
In this paper, we use a combination of photoelectron spectroscopy, mass spectrometry, and density functional theory calculations to get a detailed understanding of valence single and double ionization and the subsequent dissociation processes. This is exemplified on benchmark systems, trimetallo-dodecacarbonyls M3(CO)12 with M = Ru, Os, where the energy remaining in the molecule after photoionization can be retrieved by measuring the degree of fragmentation of the molecular ion. The intensity of different mass peaks can thus be directly related to ionization cross sections obtained by photoelectron spectroscopy. We find that the M-CO dissociation energy rises as the number of CO ligands decreases due to dissociation. Moreover, ionization of the CO ligands has a higher cross section than that of the metal center for both single and double ionization. After advanced fragmentation, a CO bond can break and the carbon atom remains bonded to the metal core. In addition, we found that the valence ionization cross sections of M3(CO)12 are maximal at about 40 eV photon energy thus showing a more pronounced shape resonance than Ru and Os-complexes with a single metal atom center. Finally, an np → nd giant resonance absorption causes a significant increase of the ionization cross section above 50 eV for Ru3(CO)12.
Department of Chemical Physics, AlbaNova University Centre, Stockholm University, Roslagstullsbacken 21, SE-106 91 Stockholm, Sweden.
Oliver
O
Schalk
Department of Chemical Physics, AlbaNova University Centre, Stockholm University, Roslagstullsbacken 21, SE-106 91 Stockholm, Sweden.
Ida
I
Josefsson
Elettra-Sincrotrone Trieste, Area Science Park, I-34149 Basovizza, Trieste, Italy.
Robert
R
Richter
Elettra-Sincrotrone Trieste, Area Science Park, I-34149 Basovizza, Trieste, Italy.
Kevin C
KC
Prince
Department of Chemical Physics, AlbaNova University Centre, Stockholm University, Roslagstullsbacken 21, SE-106 91 Stockholm, Sweden.
Michael
M
Odelius
Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden.
Melanie
M
Mucke