Light emission in the agglomeration of silver clusters

Small noble-gas droplets are generated by adiabatic expansion and travel over a heated crucible where evaporated Ag atoms are picked up. The subsequent agglomeration of these Ag atoms to clusters is associated with light emission. This effect is caused by the gain in binding energy by the clustering process leading to the ejection, preferably, of excited trimers. The heat released by condensation and coagulation of the Ag atoms on the droplets causes continuous evaporation of the noble-gas atoms, so that under suitable conditions even light emission from the decay of free Ag3∗ species could be observed and analyzed.