Spectroscopy and perturbation analysis of the A1π (v=0) state of13C16O (original) (raw)

The lowest v = 0 level of the A 1 Π state of the 13 C 16 O isotopologue of carbon monoxide has been reinvestigated with a variety of high resolution spectroscopic techniques. The A 1 Π−X 1 Σ + (0, 0) band has been studied by vacuum-ultraviolet Fourier-transform absorption spectroscopy, using the SOLEIL synchrotron as a radiation source. Spectra were obtained under quasi-static gas conditions at liquid-nitrogen temperature, room temperature and at an elevated temperature of 900 K, with absolute accuracies of 0.01−0.03 cm −1. Two-photon Doppler-free laser spectroscopy has been applied to a limited number of transitions in the A 1 Π−X 1 Σ + (0, 0) band, under collision-free circumstances of a molecular beam, yielding an absolute accuracy of 0.002 cm −1. The third technique is high-resolution Fourier-transform emission spectroscopy in the visible region applied to the B 1 Σ + −A 1 Π(0, 0) band in a gas discharge, at an absolute accuracy of up to 0.003 cm −1. With these methods rotational levels of A 1 Π (0) could be studied in both parity components up to a rotational quantum number of J = 46. The frequencies of 397 transitions were used to analyse the perturbations between the A 1 Π(0) level by vibrational levels of the D 1 ∆, e 3 Σ − , d 3 ∆, and a ′3 Σ + states.