Multiphoton ionization and fragmentation of molecules with the LCLS X-ray FEL

The photoionization of diatomic and polyatomic molecules with intense femtosecond X-ray pulses from the Linac Coherent Light Source free electron laser have been investigated using photoion spectrometry. The dominant mechanism measured is multiple core-ionization-Auger decay cycles leading to molecular fragmentation followed by the production of highly charged atomic ions. This work sheds light on fundamental aspects of matter-intense X-ray interaction and impacts research relevant to matter under extreme conditions and molecular radiation damage, pertinent to single bio-molecule imaging.