The generation of highly ionized iodine (3+), xenon (5+) and mercury (4+) atoms at pressures of ∼10− 6 Torr and laser intensities of ∼101 4 W/cm2 at 193 nm is described. A minimum energy in excess of 170 eV, corresponding to ≥ 27 photons, is required to produce Xe5 +.