High-resolution spectroscopy of the A¹Π(v′=0-10)−X¹Σ⁺(v′′=0) bands in ¹³C¹⁸O: term values, ro-vibrational oscillator strengths and Hönl–London corrections

Abstract : Our knowledge of astronomical environments containing CO depends on accurate molecular data to reproduce and interpret observations. The constant improvement in UV space instrumentation, both in sensitivity and resolution, requires increasingly detailed laboratory data. Following a long-term experimental campaign at the SOLEIL Synchrotron facility, we have acquired complete datasets on the CO isotopologues in the vacuum ultraviolet. Absorption spectra were recorded using the Fourier-transform spectrometer installed on the DESIRS beamline, providing a resolving power R > 10⁶ in the 8–12 eV range. Such resolution allows the analysis of individual line positions and strengths in electronic transitions and the location of perturbations. We continue our previous work on A–X bands of ¹²C¹⁶O and ¹³C¹⁶O, reporting here measurements for the ¹³C¹⁸O isotopologue.