1. Elettra Sincrotrone Trieste S.c.p.A., Basovizza, I-34012 Trieste, Italy
2. CNR—SPIN, UOS Salerno, I-84084 Fisciano, Italy
3. CNR—SPIN, UOS Napoli, I-80126 Napoli, Italy
4. Department
of Physics, University of Napoli Federico II, I-80126 Napoli, Italy
5. CNR—ISMN, UOS Bologna, I-40129 Bologna, Italy
6. CNR—IOM, Laboratorio TASC, I-34149 Trieste, Italy
7. Synchrotron SOLEIL, L’Orme des Merisiers, BP 48, Saint Aubin, 91192 Gif sur Yvette, France
8. Laboratoire
de Chimie Physique-Matière et Rayonnement, UPMC Université; Paris 06, CNRS, UMR 7614, F-75005 Paris, France
9. Department
of Physics, University of Milano, I-20133 Milano, Italy
10. International Centre for Theoretical Physics (ICTP), I-34100 Trieste, Italy