Precision spectroscopy and comprehensive analysis of perturbations in the A ¹ ∏(v = 0) state of ¹³ C ¹⁸ O

We have reinvestigated the A (Formula presented.) level of ¹³ C ¹⁸ O using new high-resolution spectra obtained via multi-photon laser excitation as well as with synchrotron-based Fourier-transform absorption spectroscopy of the A (Formula presented.), e (Formula presented.), d (Formula presented.), a (Formula presented.), and a (Formula presented.) bands. In addition, Fourier-transform emission spectroscopy in the visible range is performed on the (Formula presented.) band. Spectra of the B (Formula presented.) band are measured in order to tie information from the latter emission data to the level structure of A (Formula presented.). The high pressures in the absorption cell at the synchrotron and the high temperatures in the emission discharge permitted monitoring of high rotational quantum levels in A (Formula presented.) up to J=43. All information, in total over 900 spectral lines, was included in an effective Hamiltonian analysis of the A (Formula presented.) levels that are directly perturbed by the e (Formula presented.), d (Formula presented.), a (Formula presented.), D (Formula presented.), I (Formula presented.) close-lying levels and the e (Formula presented.), d (Formula presented.), a (Formula presented.) remote levels, as well being indirectly influenced by the a (Formula presented.) state. The influence of 9 further perturber levels and their interactions was investigated and are not significant for reproducing the present experimental data. This analysis leads to a much improved description in terms of molecular constants and interaction parameters, compared to previous studies of the same energy region for other CO isotopologues.