Spectroscopy and perturbation analysis of the CO A[superscript 1]Π −X[superscript 1]Σ+ (2,0), (3,0) and (4,0) bands

Abstract

The (2,0) (3,0) and (4,0) bands of the A[superscript 1]Π −X[superscript 1]Σ+ system of [superscript 12]C[superscript 16]O 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[superscript −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 A[superscript 1]Π, v = 2, v = 3 and v = 4 levels by vibrational levels of the D[superscript 1]Δ, I[superscript 1]Σ−, e[superscript 3]Σ[superscript −], d[superscript 3]Δ and a[superscript ′3]Σ+ states.