[1] CNR, Ist Struttura Mat, UOS Montelibretti, Area Ric Roma1, I-00185 Rome, Italy
[2] European XFEL GmbH, D-22761 Hamburg, Germany
[3] SLAC Natl Accelerator Lab, LCLS, Menlo Pk, CA 94025 USA
[4] Uppsala Univ, Dept Phys & Astron, SE-75120 Uppsala, Sweden
[5] SLAC Natl Accelerator Lab, PULSE, Menlo Pk, CA 94025 USA
[6] Univ Stockholm, Dept Phys, S-10691 Stockholm, Sweden
[7] Univ Connecticut, Dept Phys, Storrs, CT 06269 USA
[8] Tohoku Univ, Dept Phys, Sendai, Miyagi 9808577, Japan
[9] Synchrotron SOLEIL, F-91192 Gif Sur Yvette, France
[10] Elettra Sincrotrone Trieste, I-34149 Basovizza, Italy
[11] Texas A&M Univ, Dept Chem, College Stn, TX 77843 USA
[12] Hiroshima Univ, Dept Chem, Hiroshima, Japan