Autoionization dynamics in the valence-shell photoionization spectrum of CO

Abstract

Autoionizing Rydberg series in the valence-shell spectrum of CO have been studied by determining the high resolution relative photoionization cross section of cooled CO in the energy region 14.0–20.0 eV and by determining the vibrational branching ratios and the photoelectron angular distributions for production of CO+ X 2Σ+, v+=0–2 in the energy region 16.75–18.75 eV. Of particular interest are three prominent spectral features between 17.0 and 17.5 eV that result from interactions involving Rydberg series converging to the excited A 2Π and B 2Σ+ states of the ion. The results are discussed in the context of recent two-step multichannel quantum defect theory calculations by Leyh and Raseev (the following paper).