Dissociative multiple ionization of argon trimers and tetramers in two-color femtosecond laser fields

Abstract

We experimentally investigate the dissociative multiple ionization of argon trimers and tetramers induced by relative phase-controlled linearly and elliptically polarized two-color femtosecond laser fields. The momentum distributions and kinetic energy releases of the resulting fragments from various channels are measured in coincidence. The observed anisotropic momentum distributions indicate a preference for triple and quadruple ionization of argon trimers when one of the argon atoms is aligned parallel to the laser field polarization. By varying the relative phase of the two-color laser fields, we achieve directional control over the dissociative triple and quadruple ionization of argon trimers, facilitated by the mechanism of enhanced ionization. The measured relative phase-dependent asymmetry patterns exhibit similarity in both linearly and elliptically polarized two-color laser fields, suggesting a minimal role of electron recollision. Furthermore, we extend our investigation to the dissociative quadruple ionization of argon tetramers. These findings provide valuable insights into the van der Waals bond breaking in complex clusters and contribute to the broader understanding of laser-driven molecular fragmentation.