New quartet and doublet electronic transitions in the near-infrared emission spectrum of VO

Abstract

The emission spectrum of VO in the near-infrared has been studied by high-resolution Fourier transform spectroscopy. Rotational analyses of several new electronic transitions have been performed, which more than double the number of known states of VO. Specifically, two quartet transitions, D 4Δ-A′ 4Φ near 11 800 cm -1 and D 4Δ-A 4Π near 9600 cm -1, have given accurate data (including the absolute energies relative to X 4Σ -) for the states σδσ * D 4Δ and σδπ A′ 4Φ, and complete the characterization of the predicted low-lying quartet states of VO; these transitions also appear to be the first examples of their types to have been analyzed in detail. A new 2Δ- 2Φ transition near 9600 cm -1 (overlapping D 4Δ-A 4Π) has been assigned to one of the possible σδσ *2Δ-σδπ 2Φ transitions, and a complex group of 2Π- 2Δ transitions in the 7000 to 8000-cm -1 region has given data for the low-lying σ 2δ 2Δ state and for parts of two 2Π states. Perturbations are widespread throughout the spectra. Using arguments based on the vanadium nuclear hyperfine structure, the spin-orbit coupling, and the bond lengths, it has been possible to assign electron configurations for all the observed electronic states; about half the predicted low-lying states of VO are now known. © 1987.