Electronic bands of scandium monocarbide, ScC, in the region 14 140–16 000 cm−1

Scandium monocarbide molecules, ScC, have been prepared by the reaction of 532 nm laser-ablated Sc metal with acetylene or methane under supersonic jet-cooled conditions. Electronic spectra of Sc12C and Sc13C have been recorded in the region 14 140–16 000 cm−1 using laser-induced fluorescence, and about 40 bands of each isotopomer have been analyzed rotationally. Wavelength resolved emission spectra have been obtained for many of them. The results show that Sc12C has a 2Πi ground state, with a bond length of 1.952 A. Its vibrational frequency and spin-orbit coupling constant are 648 cm−1 and −39.47 cm−1, respectively (631 cm−1 and −39.32 cm−1 in Sc13C). Lying 155.58 cm−1 above the X2Π3/2 level (154.72 cm−1 in Sc13C) is a 4Π5/2 level, the lowest spin-orbit component of a 4Πi state. The excited states at higher energy are very complicated. Bands from both the doublet and quartet spin manifolds are present, and there are strong doublet-quartet interactions which induce many nominally-forbidden bands violating the selection rule ΔS = 0. Eight excited electronic states have been recognized, including four 4Δ states. These 4Δ states represent four of the five 4Δ states from the electron configurations (C 2pσ)2 (C 2pπ)2 (Sc 3dδ)1 and (C 2pσ)1 (C 2pπ)2 (Sc 4sσ)1 (Sc 3dδ)1.Scandium monocarbide molecules, ScC, have been prepared by the reaction of 532 nm laser-ablated Sc metal with acetylene or methane under supersonic jet-cooled conditions. Electronic spectra of Sc12C and Sc13C have been recorded in the region 14 140–16 000 cm−1 using laser-induced fluorescence, and about 40 bands of each isotopomer have been analyzed rotationally. Wavelength resolved emission spectra have been obtained for many of them. The results show that Sc12C has a 2Πi ground state, with a bond length of 1.952 A. Its vibrational frequency and spin-orbit coupling constant are 648 cm−1 and −39.47 cm−1, respectively (631 cm−1 and −39.32 cm−1 in Sc13C). Lying 155.58 cm−1 above the X2Π3/2 level (154.72 cm−1 in Sc13C) is a 4Π5/2 level, the lowest spin-orbit component of a 4Πi state. The excited states at higher energy are very complicated. Bands from both the doublet and quartet spin manifolds are present, and there are strong doublet-quartet interactions which induce many nominally-forbidden bands violatin...