Rotational analysis of the blue–green system of scandium oxide

Abstract

The blue–green emission system of scandium oxide has been reanalyzed as 2Σ → 2Σ instead of 2Σ → 4Σ, as was previously suggested. The fine doubling seen in the spectrum (~0.25 cm−1) is attributed to nuclear hyperfine effects, the ground state being essentially a bβS coupling case and the excited state, bβJ. The hyperfine splitting in the upper 2Σ level is very small and has not been observed directly, whereas the ground-state interaction is large, indicating that the ground term arises from an essentially 4sσ configuration. The ground-state splitting alone is responsible for the observable hyperfine structure features of the spectrum.The transition in the orange–red is, accordingly, assigned as 2Π → 2Σ, the splitting once again being confined to the ground term. The details of this system will be dealt with in a separate paper.