Transient change in the velocity distribution functions of sputtered atoms during initial dose in ion-beam bombardment

Velocity distribution functions of sputtered iron-atoms under argon-ion bombardment were directly measured with a rapid-frequency-scan dye laser. Each measured profile was fitted with the Thompson formula, and an equivalent surface binding energy was estimated at each ion dose. The surface binding energy thus obtained was near the formation energy of iron in iron oxides at a low ion dose (less than 1 x 1019 ions/m2), but approached the sublimation energy of a pure iron above 5 x 1019 ions/m2. (author)