On the major mode of multiphoton multiple ionisation

Abstract

There has been discussion recently as to whether the dominant mode of multiphoton ionisation in Xe is sequential (single-electron) or collective (many-electron) in character. In order to address this question, the authors have performed an experiment with the isoelectronic molecule HI using a laser of a peak power density 3*1015 W cm-2. The results show categorically that the process cannot be collective. In addition, they indicate how the dynamics of the multielectron dissociative ionisation of a molecule such as HI can be investigated on a time scale of femtoseconds using a picosecond laser.