Magnetic hyperfine interactions in the electronic spectra of diatomic molecules II. Magnetic interactions in Hund’s case ( c ) and the spectram of BiO

Abstract

The magnetic hyperfine interaction in Hund’s case ( c ) diatomic molecules is investigated by the method of spherical tensors and time-reversed angular momenta. Explicit expressions for the matrix elements are given, so too are expressions for the first and second order energies for an |Ω| = 1/2 state. The equations are applied to the electronic spectrum of BiO (Barrow, Gissane & Richards 1967) and the observed line widths are accounted for in terms of a magnetic hyperfine interaction with the 209 Bi nucleus. The electric quadrupole hyperfine interaction in BiO is also investigated and shown to be incapable of accounting for the observed effects.