Study of the A1Π→X1Σ+ Bands of B11F with a Vacuum Echelle Spectrograph

The A1Π→X1Σ+ bands of B11F which had been found by Chretien and Miescher were now studied with the aid of a higher dispersion spectrograph and more accurate molecular constants were obtained, i.e., A1Π:Te=51 157.48 cm−1,ωe=1264.96 cm−1,ωexe=12.53 cm−1,ωeye=−0.242 cm−1,Be=(c)1.4205 cm−1,(d)1.4207 cm−1,αe=0.0165 cm−1,γe=−0.00057 cm−1,D=7×10−6 cm−1,re=1.3047A;X1Σ+:ωe=1402.13 cm−1,ωexe=11.84 cm−1,ωeye=+0.056 cm−1,Be=1.5107 cm−1,αe=0.0165 cm−1,γe=−0.00015 cm−1,D=7×10−6 cm−1,re=1.2652A. Λ‐type doubling was observed in the A1Π state, and a brief discussion of the doubling is given in this report.