Theoretical study of low-lying 1Σ− and 1Δ states of CO

Abstract

A b initio calculations of electronic wave functions and potential energy curves for each of two low-lying states of 1Σ− and 1Δ symmetry for CO are reported. The second state of each symmetry has Rydberg character. Computed spectroscopic constants for the metastable I 1Σ− and D 1Δ states appear to be in good agreement with experimental data. The radiative lifetimes of vibrational levels within the I 1Σ− and D 1Δ states have been computed considering two types of decay: cascade within each electronic state, and transitions to the nearby A 1Π. It is shown that the v=0 levels of each metastable electronic state have very long lifetimes. The observation of these metastable states in electron impact experiments is discussed in light of our results.