Return of an electronic wavefunction to the core

Abstract

Picosecond laser pulses are used to excite xenon atoms to Rydberg states and photoionise in a three-plus-one-photon ionisation process. When high Rydberg levels are excited, an electronic wavepacket is created. This wavepacket does not return to the core during the laser pulse: the direct four-photon ionisation is not enhanced. When lower Rydberg levels are excited the electronic wavefunction does return to the core: the ionisation is enhanced. The authors observe the transition from enhanced to non-enhanced ionisation.