Emission spectroscopy of a new 2Δ-12Δ system of VO

High-resolution spectra of VO have been reinvestigated in the 12 000-31 000 cm−1 region. VO was produced in a vanadium hollow cathode lamp by discharging 1.5 Torr of Ar and the spectra were recorded using a Fourier transform spectrometer. The oxygen needed to produce VO was present in the system as an impurity. Three new bands observed in the 21 000-22 100 cm−1 region have been attributed to a new 2Δ-12Δ electronic transition of VO. Two bands, with origins near 21 044 and 22 038 cm−1, have been assigned as the 0-1 and 0-0 bands of the 2Δ3/2-12Δ3/2 sub-band while a weak band with an origin near 21 975 cm−1 has been assigned as the 0-0 band of the corresponding 2Δ5/2-12Δ5/2 sub-band. A rotational analysis of these sub-bands has been obtained and spectroscopic constants have been extracted. The 12Δ state is known from the previous analyses of the doublet transitions of VO in the near infrared. The present observation has allowed the determination of the vibrational interval ΔG1/2 and the equilibrium rotational constants for the 12Δ3/2 state.