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

Abstract

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⁺ (υ = 0) → A¹Π (υ = 3, 4, and 5) Ångström system. These are combined with high-resolution photoabsorption measurements of the ¹²C¹⁷O B¹Σ⁺ (υ = 0) ← X¹Σ⁺ (υ = 0) and C¹Σ⁺ (υ = 0) ← X¹Σ⁺ (υ = 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, υ = 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.