Electronic states and spectra of BiS

NIR/VIS emission spectra of BiS were measured in the 5800-25 000 cm−1 region with a Fourier-transform spectrometer. BiS was produced by reaction of bismuth and sulfur vapor and excited by energy transfer from metastable oxygen O2(a1Δg) in a fast-flow system. The spectrum of BiS was found to be closely related to that of the previously studied BiO radical [O. Shestakov et al., J. Mol. Spectrosc. 190 (1998) 28-77]. Five transitions connecting the Ω-components of the first three excited states, A4Π(A13/2, A21/2), B2Π(B11/2), and C4Σ−(C11/2, C23/2), with the components of the strongly split ground state, X2Π(X11/2, X23/2, have been observed and analyzed.