VIS and VUV spectroscopy of ¹²C¹⁷O and deperturbation analysis of the A¹Π, ν = 1-5 levels

High-accuracy dispersive optical spectroscopy measurements in the visible (VIS) region have been performed on the less-abundant ¹²C¹⁷O isotopologue, observing high-resolution emission bands of the B¹Σ⁺ (ν = 0) → A¹Π (ν = 3, 4, and 5) Ångström system. These are combined with high-resolution photoabsorption measurements of the ¹²C¹⁷O B¹Σ⁺ (ν = 0) ← X¹Σ⁺ (ν = 0) and C¹Σ⁺ (ν = 0) ← X¹Σ⁺ (ν = 0) Hopfield-Birge bands recorded with the vacuum-ultraviolet (VUV) Fourier transform spectrometer, installed on the DESIRS beamline at the SOLEIL synchrotron. The frequencies of 429 observed transitions have been determined in the 15 100-18 400 cm^-1 and 86 900-92 100 cm^-1 regions with an absolute accuracy of up to 0.003 cm^-1 and 0.005 cm^-1 for the B-A, and B-X, C-X systems, respectively. These new experimental data were combined with data from the previously analysed C → A and B → A systems. The comprehensive data set, 982 spectral lines belonging to 12 bands, was included in a deperturbation analysis of the A¹Π, ν = 1-5 levels of ¹²C¹⁷O, taking into account interactions with levels in the d³Δ_i, e³Σ^-, a′³Σ⁺, I¹Σ^- and D¹Δ states. The A¹Π and perturber states were described in terms of a set of deperturbed molecular constants, spin-orbit and L-uncoupling interaction parameters, equilibrium constants, 309 term values, as well as isotopologue-independent spin-orbit and rotation-electronic perturbation parameters.