Precision spectroscopy and comprehensive analysis of perturbations in the A1∏(v=0) state of 13C18O

Abstract

We have reinvestigated the A[chemical formula] level of 13C18O using new high-resolution spectra obtained via multi-photon laser excitation as well as with synchrotron-based Fourier-transform absorption spectroscopy of the A[chemical formula], e[chemical formula], d[chemical formula], a[chemical formula], and a[chemical formula] bands. In addition, Fourier-transform emission spectroscopy in the visible range is performed on the[chemical formula] band. Spectra of the B[chemical formula] band are measured in order to tie information from the latter emission data to the level structure of A[chemical formula]. 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[chemical formula] up to J=43. All information, in total over 900 spectral lines, was included in an effective Hamiltonian analysis of the A[chemical formula] levels that are directly perturbed by the e[chemical formula], d[chemical formula], a[chemical formula], D[chemical formula], I[chemical formula] close-lying levels and the e[chemical formula], d[chemical formula], a[chemical formula] remote levels, as well being indirectly influenced by the a[chemical formula] 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.