Chemiluminescent reaction (Ba + Cl

Chemiluminescence produced by the reactive collision of barium and chlorine molecule on an 8000 argon cluster is investigated. The binary collision Ba + Cl2 on the cluster leads to the observation of the reaction intermediate BaCl2 as the dominant luminescent product whereas in the gas phase, under the single collision regime, the reaction leads exclusively to the formation of the radical pair BaCl∙ + CL This result is interpreted as a very efficient trapping of the BaCl2 intermediate by the cluster. Trapping mechanisms are discussed