Spin–orbit interaction between c 3Σ+ and B 1Π states of ScF: Effects on the fine and hyperfine structures

The introduction of an off‐diagonal spin–orbit interaction element in the Hamiltonian matrix representing the close‐lying B 1Π and c 3Σ+ states of ScF allows us to interpret the anomalies previously observed, i.e., the large Λ‐type doubling in B 1Π and the large spin‐splitting in c 3Σ+ at v=0, both of which decrease rapidly with increasing vibration. Deperturbed molecular constants for the v=0,1,2 levels in both states, together with values of the interaction parameter, are obtained from the numerical treatment of the wave numbers of 1454 lines in the B 1Π→X 1Σ+(0‐1), (1‐1), (2‐0), (2‐2), and c 3Σ+→X 1Σ+(0‐1), (1‐0), (2‐0) bands. The interaction between B 1Π and c 3Σ+ is greatest at v=0 and decreases rapidly with increasing v. The model of the states including hyperfine effects is then used to interpret the observed hyperfine structure which is attributed to strong interaction between the 4sσ3dσ electrons and the 45Sc nucleus of spin 7/2. The hyperfine structure of the rotational levels in B 1Π(v=0,1,2) a...