| The optical transitions of supersonically cooled OsN have been investigated in the range from 19 200 to 23 900 cm-1 using resonant two-photon ionization spectroscopy. More than 20 vibronic bands were observed, 17 of which were rotationally resolved and analyzed. The ground state is confirmed to be 2Δ5/2, deriving from the 1σ 2 2σ2 1π4 1δ3 3σ2 electronic configuration. The X 2Δ5/2 ground state rotational constant for 192Os14N was found to be B0 = 0.491 921(34) cm-1, giving r0 = 1.620 42(6) Å (1σ error limits). The observed bands were grouped into three band systems with Ω&feet; = 7/2 and four with Ω&feet; = 3/2, corresponding to the three 2&PHgr;7/2 and four 2&Pgr;3/2 states expected from the 1σ2 2σ2 1π4 1δ3 3σ1 2π 1 and 1σ2 2σ2 1π 4 1δ2 3σ2 2π1 electronic configurations.;The optical spectrum of diatomic IrSi has been investigated for the first time, with transitions observed in the range from 17 200 to 23 850 cm -1 (581 - 419 nm). A rich spectrum has been recorded, consisting of 14 electronic band systems and a number of unclassified bands. Thirty-one bands have been investigated with rotational resolution, allowing the ground state to be identified as X2Δ5/2 arising from the 1σ2 1π4 2σ2 1δ3 3σ2 configuration. The ground X2Δ5/2 state is characterized by ΔG 1/2 = 533 cm-1 and r0 = 2.0899(1) Å for the more abundant isotopic form, 193Ir28Si (57.8%). The measured excited electronic states have equilibrium bond lengths ranging from 2.17 to 2.25 Å and vibrational frequencies ranging from 365 to 452 cm-1.;The optical spectrum of the linear CuCCH molecule has been investigated for the first time, using resonant two-photon ionization spectroscopy employing ArF (193 nm) or F2 (157 nm) excimer radiation for photoionization. Scans over the range 19 400- 25 200 cm-1 were conducted, leading to the observation of three electronic band systems. These are identified as the [20.2] ã1 ← X˜1Σ +, the Ã1Σ+ ← X˜ 1Σ+, and the [24.7] B˜1&Pgr; ← X˜ 1Σ+ systems, although only the first two have been rotationally resolved. The ã1 state is tentatively assigned as having 3&Pgr;1 symmetry, becoming optically accessible through spin-orbit interaction with the B˜1&Pgr; state. |
