CHEMILUMINESCENT REACTION (BA-2) WITHIN LARGE ARGON CLUSTERS(CL)

Chemiluminescence produced by the reactive collision of barium and chl orine molecule on an 8000 argon cluster is investigated. The binary co llision Ba + Cl-2 on the cluster leads to the observation of the react ion intermediate BaCl2 as the dominant luminescent product whereas in the gas phase, under the single collision regime, the reaction leads e xclusively to the formation of the radical pair BaCl + Cl. This resul t is interpreted as a very efficient trapping of the BaCl2 intermediat e by the cluster. Trapping mechanisms are discussed.