We report here the first positive ESR identification of a neutral mixed triatomic transition-metal cluster, CuAgCu, which has been produced at 77 K by cocondensing 63Cu atoms ( I = 3/2), Io7Ag (I = atoms, and C6D6 on the cold surface of a rotating cryo ~ tat . ~ ~ ~ Isotopically pure silver (98.22% 107Ag)9 and copper (98.89% 63Cu)9 were chosen for these experiments because of the anticipated complexity of the spectra from natural copper and silver. The EPR ...