Absorption Spectrum of H2 in the Vacuum-uv Region. II. Rydberg Series Converging to the First Six Vibrational Levels of the H2+ Ground State

The absorption spectrum of H2 at liquid-nitrogen temperature has been further investigated with a 6.65-m vacuum spectrograph in the 800–600-Å region. Eleven distinct groups, each consisting of 8–30 absorption lines, have been observed at wavelengths converging to the levels υ = 0–5 of the H2+ ground state. Evidently these individual groups are Rydberg series. Consideration of l-uncoupling effects permits these series to be assigned as R(0), R(1), and Q(1) series in npπ ← X transitions and as R(0) series in npσ ← X transitions. A new value of the ionization energy of H2, 124 418.4 ± 0.6 cm−1, has been obtained from Rydberg series converging to the υ = 0 level of the H2+ ground state.