New findings on the sputtering of neutral metal clusters

摘要: Neutral copper and aluminum clusters containing up to 20 12 atoms, respectively, were observed in the sputtering of polycrystalline metals by 3.75 or 3.9 keV Ar+ ions. The postionized 6.4 eV photons from an ArF excimer laser mass analyzed a time-of-flight spectrometer. yields estimated their concentrations are shown for first time exhibit power-law dependence on number atoms cluster. kinetic energy distributions Cu through Cu6 measured, cluster found resemble atom distribution, agreement with our earlier data. Collision-cascade-based models cannot predict yield distribution Several alternate considered, but none is be satisfactory explaining large emission. For small (n < 3) clusters, superposition two more mechanisms may help explain observations.