Analyse Rotationnelle de la Bande (0,0) du Système Orange de ScO

The orange system of ScO has been reanalyzed as a 2Π → 2Σ transition. We have observed all the branches which are compatible with the selection rules ΔJ = 0, ± 1. We have not detected the hyperfine structure in the excited state, the coupling case being therefore aβ. The magnetic hyperfine interaction inducing the ground state doubling is the only one which appears; it has been analyzed by other authors who have shown that the coupling case for this state is of the type bβS.The use of an alloy hollow-cathode lamp, cooled with liquid nitrogen, has enabled us to improve the frequency measurements. The values of the constants have been obtained by a method by which, working directly with the Hamiltonian, the introduction of each parameter can be justified. The study of the Λ doubling in 2Π3/2 and 2Π1/2 levels leads us to values of ξ and η very close to those predicted for a pure precession case.