High resolution spectroscopy and perturbation analysis of the CO A¹Π −X¹Σ⁺ (0,0) and (1,0) bands

Abstract

The two lowest-v′ (0,0) and (1,0) bands of the A¹Π −X¹Σ⁺ system of ¹²C¹⁶O have been investigated by two high-resolution spectroscopic methods. A vacuum ultraviolet Fourier-transform spectrometer, illuminated by synchrotron radiation, was applied to record a jet-cooled spectrum and a room temperature static gas spectrum, resulting in absolute accuracies of 0.01−0.02 cm⁻¹. In addition two-photon Doppler-free laser spectroscopy has been applied to a limited number of rotational lines, resulting in an accuracy of 0.002 cm⁻¹. The data were used to perform an improved analysis of the perturbations in the A¹Π, v = 0 and v = 1 levels by vibrational levels in the D¹Δ, I¹Σ⁻, e³Σ⁻, d³Δ. and a′³Σ⁺ states.

Keywords:

• ultraviolet spectra
• FT-spectroscopy
• Doppler-free laser spectroscopy
• perturbation analysis
• carbon monoxide

Acknowledgements

This work was supported by the Netherlands Astrochemistry Program of NWO (CW-EW). Staff of the SOLEIL synchrotron is thanked for their hospitality and support.

Notes

^aData from Ref. [13] and converted, see text. ^bData from Ref. [38] and converted, see text. ^cConstant fixed to that of d³Δ, v = 5 as first-order approximation. ^dConstant fixed to that of a′³Σ⁺, v = 9 as first-order approximation. ^eData from Ref. [36]. ^fConstant fixed to that of I¹Σ⁻, v = 2 as first-order approximation.