Molecular imaging with X-ray free electron lasers: dream or reality?

Abstract: X-ray Free Electron Lasers (XFEL) are revolutionary photons sources, whose ultrashort, brilliant pulses are expected to allow single molecule diffraction experiments providing structural information on the atomic length scale. This ultimate goal, however, is currently hampered by several challenging questions basically concerning sample damage, Coulomb explosion and the role of nonlinearity. By employing an original \emph{ab-initio} approach, as well as exceptional resources of parallel computing, we address these issues showing that accurate XFEL-based single molecule imaging will be only possible with ultrashort pulses of half of femtosecond, due to significant radiation damage and the formation of preferred multi-soliton clusters which reshape the overall electronic density of the molecular system at the femtosecond scale.