STM IDENTIFICATION OF SILVER OLIGOMER CLUSTERS PREPARED BY RADIOLYSISIN AQUEOUS-SOLUTION

Silver oligomers prepared by radiolysis in aqueous solution in the pre sence of polyacrylate and absorbing at approximate to 290 nm have been imaged by STM in air after being deposited on a HOPG surface. Clear i mages with atomic resolution are observed, showing flat clusters of 0. 7 nm. Each cluster contains seven (or possibly eight) atoms correspond ing to the stoichiometry (Ag-4+m)(m+), m=3 (or 4), for the clusters in aqueous solution. No interference due to the polyanion (present in th e solution as a stabilizing agent) is found for adsorbate densities.