High-resolution absorption spectrum of jet-cooled CS2 between 70 500 and 81 550 cm−1: np and nf Rydberg series converging to the first ionization potential

The absorption spectrum of jet-cooled CS2 was photographed between 70 500 and 81 550 cm−1 at a resolution limit of 0.0008 nm, i.e., 0.4 to 0.5 cm−1. Wave numbers of over 200 features are reported and assigned in terms of ⋯2πg3np (n=5–25) and nf (n=4–17) allowed transitions—electronic origin bands and vibronic 101 bands corresponding to excitation of the totally symmetric stretching vibrational mode in the excited electronic states—as well as forbidden ⋯2πg3nsσ (n=5–7), ndσ (n=4 and 5), and ndδ (n=3–5) g−g transitions—201 and 212 bands involving excitation of the bending vibrational mode in the corresponding excited 1,3Πg states—, and the (⋯2πu3A2Πu)4sσg 1Πu allowed transition, first term of a series converging to the second ionization limit. Ab initio calculations of the electronic energies and transition moments for effective principal quantum numbers about 4 and 5 are carried out for all the observed series. Rotational band contours are calculated using Hund’s case (e) representation for one- and three-...