The structure of the forbidden transition λ = 647.5 nm (
) in Bi i has been completely analyzed by means of a Fourier-transform spectrometer. In addition to the 12 components corresponding to ΔF = 0, ±1, two components corresponding to ΔF = ±2 have been observed for the first time to our knowledge. From the intensity calculations, it is estimated that the admixture of electric-quadrupole radiation is about 20%, in agreement with the earlier theoretical calculations of Garstang [
J. Res. Nat. Bureau Stand. Sect. A
1964)]. The A and B constants are also calculated and compared with earlier results. The value of the level
has been recalculated to be 15437.51 ± 0.01 cm−1.
© 1984 Optical Society of America