Fourier-transform spectroscopy of ¹³C¹⁷O and deperturbation analysis of the A¹Π (υ=0–3) levels

The high-resolution B¹Σ⁺→A¹Π (0, 0) and (0, 3) emission bands of the less-abundant ¹³C¹⁷O isotopologue have been investigated by Fourier-transform spectroscopy in the visible region using a Bruker IFS 125HR spectrometer at an accuracy 0.003 cm^-1. These spectra are combined with high-resolution photoabsorption measurements of the ¹³C¹⁷O B¹Σ⁺←X¹Σ⁺ (0, 0), B¹Σ⁺←X¹Σ⁺ (1, 0) and C¹Σ⁺←X¹Σ⁺ (0, 0) bands recorded with an accuracy of 0.01 cm^-1 using the vacuum ultraviolet Fourier-transform spectrometer, installed on the DESIRS beamline at the SOLEIL synchrotron. In the studied 17,950–22,500 cm^-1 and 86,800–92,100 cm^-1 regions, 480 transitions have been measured. These new experimental data were combined with data from the C→A and B→A systems, previously analyzed in ¹³C¹⁷O. The frequencies of 1003 transitions derived from 12 bands were used to analyze the perturbations between the A¹Π (υ=0–3) levels and rovibrational levels of the d³Δ_i, e³Σ^-, a'³Σ⁺, I¹Σ^- and D¹Δ states as well as to a preliminary investigation of weak irregularities that appear in the B¹Σ⁺ (υ=0) level. Deperturbed molecular constants and term values of the A¹Π state were obtained. The spin-orbit and L-uncoupling interaction parameters as well as isotopologue-independent spin-orbit and rotation-electronic perturbation parameters were derived.