Resonant Two-Photon Ionization Spectroscopy of Jet-Cooled OsSi

The optical spectrum of diatomic OsSi has been investigated for the first time, with transitions observed in the range from 15 212 to 18 634 cm^-1 (657-536 nm). Two electronic band systems have been identified along with a number of unclassified bands. Nine bands have been investigated at rotational resolution, allowing the ground state to be identified as X 3 Σ 0 + -, arising from the 1σ²1π⁴2σ²3σ²1δ² configuration. The ground X 3 Σ 0 + - state is characterized by r_e = 2.1207(27) Å and ΔG_1/2″ = 516.315(4) cm^-1 for the most abundant isotopologue, ¹⁹²Os²⁸Si (38.63%). The A1 excited electronic state, which is thought to be primarily ³Π₁ in character, is characterized by T₀ = 15 727.7(7) cm^-1, ω_e = 397.0(7) cm^-1, and r_e = 2.236(16) Å for ¹⁹²Os²⁸Si. The B1 excited electronic state is characterized by T₀ = 18 468.71 cm^-1, ΔG_1/2 = 324.1 cm^-1, and r_e = 2.1987(20) Å for ¹⁹²Os²⁸Si and is thought to be primarily ¹Π₁ in character. These results are placed in context through a comparison to other transition metal carbides and silicides.