We report observations of nonequilibrium charge state distributions of slow, highly charged ͑331 # q # 751͒ ions after transmission of thin carbon foils. Charge equilibration times are determined directly from the dependencies of exit charge states on projectile velocity ͑0.5 3 10 6 , y , 10 6 m͞s͒ and foil thickness (5 -10 nm). Ions like Xe 441 and Au 681 are found to equilibrate inside of solid matter in a time of only 7 fs. [S0031-9007(99)09368-0]

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Spectra of positively charged secondary ions from thermally grown SiO 2 films were recorded in a time-of-flight secondary ion mass spectrometry scheme. Ablation of cluster ions was induced by the impact of slow ͑4 keV/u͒ Au 69ϩ projectiles. The intensities of Si x O y H z ϩ , ͑xϭ1-22, yϭ1-44, z ϭ0-7͒ clusters are found to depend sensitively on the oxygen to silicon ratio and also on the hydrogen content. We find that oxygen rich clusters, yϭ2xϩ1, and, in one case, yϭ2xϩ2, can be stabilized by the incorporation of two additional hydrogen atoms in the cluster.

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