We report on mass-selected molybdenum dimers; (Mo-2) and trimers (Mo-3) in argon matrices via resonance Raman spectroscopy. The resonance Raman spectrum of Mo-2 displays lines at 394.5(12), 445.0(18), and 473,3(15) cm(-1), with several overtones observed for the most intense 394.5 cm(-1) line. The trimer (Mo-3) displays absorption in the 575-625 nm region with a maximum at similar to600 nm. Excitation into this region gives Raman lines at 224.5(5), 236.2(8), 386.8(12), and 446.9(7) cm(-1). They are assigned to nu(3)(a(1)), nu(2)(b(1)), nu(1) (a(1)) (the bend, antisymmetric stretch, and symmetric stretch) and 2nu(2) respectively.