Multi-Electron Ionization and Coulomb Explosion of the IBr Molecule in the Near-Infrared Femtosecond Laser Field

The DC-sliced ion velocity map imaging approach was used to analyze the multi-electron ionization and subsequent Coulomb explosion of an IBr molecule exposed to a near-infrared femtosecond laser field. The existence of the molecular ions up to IBr7+ was observed in the experiment, and a series of Coulomb explosion channels are assigned. According to the "ladder-path" ionization model, the multi-electron ionization paths of IBr molecules are determined. We find that the charge transfer process does not occur during ionization, and the presence of higher charge states can be explained by considering the higher-order ionization process.