Prompt in situ emission of gold adducts from single impacts of large gold clusters on organics solids

We report the first observation of single impacts of 136 keV Aun4+ (100 ≤ n ≤ 400) on organic solids, generating prolific emission of Au and Au2 - containing fragments and molecular ions. We show that the individual impacting cluster is both the source of energy stimulating the emission, and the donor of atoms for adducts synthesis. The emission of Au and Au2 was observed when n ≥ 100. The most abundant species is Au(CN)2−. The adduct yields behave as follows when the projectile size varies from n = 100 to 400: (a) they increase with n; (b) the dependence with n for the formation of Au(CN)2− differs from those for more complex species suggesting different pathways of synthesis; (c) the combined yields of the Au or the Au2 - adducts are the same for different targets. There is evidence that the projectiles were implanted virtually intact in the organic targets, thus, the adduct synthesis involves a small number of Au atoms ablated from the projectile, which implies extensive ionization of the detached atoms. The abundance of three-body assemblies, e.g. Au(CN)2−, Au(CN) (M–H)−, suggests that the adduct formation occurs likely in a dense phase.