[1] Univ NOVA Lisboa, Fac Ciencias & Tecnol, Dept Fis, CEFITEC, P-2829516 Caparica, Portugal
[2] Univ Iceland, Dept Chem, Dunhagi 3, IS-107 Reykjavik, Iceland
[3] Univ Iceland, Sci Inst, Dunhagi 3, IS-107 Reykjavik, Iceland
[4] Max Planck Inst Chem Energiekonvers, Dept Inorgan Spect, Stifistr 34-36, D-45470 Mulheim, Germany
[5] Univ Florida, Dept Chem, Gainesville, FL 32611 USA