Resonance-enhanced x-ray multiple ionization of a polyatomic molecule

Extremely high charge states of atoms and molecules can be created when they are irradiated by intense x-ray pulses. At certain x-ray photon energies, electron ejection from atoms can be drastically enhanced by transient resonances created during the sequential ionization process. Here we report on the observation of such resonance effects in a molecule, CH3I, and show the photon-energy-dependent shift of resonance-induced structures in ion charge state distributions. By comparing the ion charge state distribution of CH3I with that from ionization of atomic xenon, molecule-specific features are observed, which can be attributed to ultrafast intramolecular charge rearrangement. In addition, we experimentally demonstrate that the charge-rearrangement-enhanced xray ionization of molecules, previously found with hard x rays, also plays a role in the soft x-ray regime.