Gas-phase oxidation of silver: the reaction of silver clusters with ozone

Abstract

In a device which produces a metallic flow intermediate to that of a standard effusive source (atoms and small percent diatomics) and laser vaporization-plasma formation followed by rare gas entrainment at pressures exceeding several torr (wide cluster distribution), the reaction of small silver clusters, M/sub n/, n greater than or equal to 3, with ozone has been observed in the gas phase at pressures in the millitorr range. Chemiluminescent emission from the products AgO and what appear to be Ag2O and Ag/sub x/O, where x greater than or equal to 3, has been monitored. We associated a red shift of the spectral features with the increasing size of the metal cluster oxide. The spectral data combined with supplementary thermodynamic information demonstrate that AgO* with enough energy to account for the observed chemiluminescence cannot be produced through the reaction of either Ag or Ag2 with O3. The smallest cluster whose reaction can yield excited states of AgO is the trimer. The formation of Ag2O* can also be achieved through reaction of the trimer; however, it may also be accounted for via reaction of higher clusters. 20 references, 1 figure.