Ag/Au/S ternary clusters were generated by laser ablation on Ag/Au/S mixtures and detected with a time-of-flight (TOF) mass spectrometer. The results show that Ag/S binary clusters, Au/S binary clusters, and Ag/Au/S ternary clusters were produced simultaneously and that the main cluster series include (Ag~2~n~+~1S~n~-~1)^+、 (Ag~2~n~-~1S~n)^-, (Ag~2~nAuS~n)^+ and (Ag~2~nAuS~n~+~1)^-. By correlating them with sulfur-plus-gold sensitization centers in photographic emulsions, the authors point out that the cluster cations and anions can act as photoelectron trap and positive hole trap, respectively.

Key words: SILVER, GOLD, SULFUR, TIME-OFF FLIGHT MASS SPECTROMETRY