Electronic bands of scandium monocarbide, ScC, in the region 14 140-16 000 cm(-1)

摘要

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 (ScC)-C-12 and (ScC)-C-13 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 (ScC)-C-12 has a (2)Pi(i) ground state, with a bond length of 1.952 angstrom. 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 (ScC)-C-13). Lying 155.58 cm(-1) above the X-2 Pi(3/2) level (154.72 cm(-1) in (ScC)-C-13) is a (4)Pi(5/2) level, the lowest spin-orbit component of a (4)Pi(i) 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 Delta S = 0. Eight excited electronic states have been recognized, including four (4)Delta states. These (4)Delta states represent four of the five (4)Delta states from the electron configurations (C 2p sigma)(2) (C 2p pi)(2) (Sc 3d delta)(1) and (C 2p sigma)(1) (C 2p pi)(2) (Sc 4s sigma)(1) (Sc 3d delta)(1). Published by AIP Publishing.