The A2Π–X2Σ+ Band System of YO

Abstract

YO bands are conspicuous in the spectra of S stars. The laboratory spectrum of the A ^2 Π–X ^2 Σ ^+ electronic transition has been recorded with a Fourier transform spectrometer using a composite-wall hollow cathode lamp source. The A ^2 Π–X ^2 Σ ^+ transition with ${v}^{{\prime} }\leqslant 4$ and v ″ ≤ 4 has been rotationally analyzed using the modern spectral fitting program PGOPHER. Vibronic band strengths were calculated using an ab initio transition dipole moment function. A line list for the A ^2 Π–X ^2 Σ ^+ transition is provided and can be utilized in the modeling of S stars.

Keywords

• Rotational spectroscopy
• Spectral line lists
• Molecular spectroscopic constants
• S stars