Spectroscopy and perturbation analysis of the CO A¹Π −X¹Σ⁺ (2,0), (3,0) and (4,0) bands

ABSTRACT

The (2,0) (3,0) and (4,0) bands of the A¹Π −X¹Σ⁺ system of ¹²C¹⁶O have been re-investigated by high-resolution vacuum ultraviolet absorption spectroscopy. A vacuum ultraviolet Fourier-transform spectrometer, illuminated by synchrotron radiation, was applied to record a jet-cooled spectrum, a room temperature static gas spectrum and a high-temperature (900 K) quasi-static gas spectrum, resulting in absolute accuracies of 0.01−0.02 cm⁻¹ for the rotational line frequencies. Precise laser-based data were included in the analysis allowing for a highly accurate determination of band origins. Rotational levels up to J = 52 were observed. The data were used to perform an improved analysis of the perturbations in the A¹Π, v = 2, v = 3 and v = 4 levels by vibrational levels of the D¹Δ, I¹Σ⁻, e³Σ⁻, d³Δ and a′³Σ⁺ states.

Keywords:

• Ultraviolet spectra
• FT-spectroscopy
• doppler-free laser spectroscopy
• perturbation analysis
• carbon monoxide

Acknowledgements

We are grateful to the general and technical staff of SOLEIL for providing beam time under project no. 20120653.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Dutch Astrochemistry Program of NWO (CW-EW).