We have studied the ionic outcome from the interaction of intense laser light with large argon and xenon clusters. Ions with initial energies of several 100 keV are charge and energy selected using a magnetic deflection time-of-flight mass spectrometer. For argon clusters, Coulomb repulsion is the key process in the explosion mechanism, whereas for xenon we observe a mixture of Coulomb repulsion and hydrodynamic expansion. Coulomb explosion is the preferred decay channel for smaller clusters and it is also responsible for the production of the most energetic ions. Our results can be understood on the basis of a charged sphere model of cluster-sized plasmas.

• Received 23 June 1997

DOI:https://doi.org/10.1103/PhysRevLett.80.261