New Absorption Spectra of Atomic and Molecular Oxygen in the Vacuum Ultraviolet. I. Rydberg Series from O I Ground State and New Excited O2 Bands

Abstract

Absorption series of ground-state atomic oxygen (3P2,1,0) and new O2 bands in discharged He–O2 mixtures have been observed in the 600–1000-Å wavelength region. The O I spectrum consists of the nine allowed Rydberg series converging to the three lowest states of O II: 4S3/20, 2D5/2,3/20, and 2P3/2,1/20. The series observed were as follows: 2p3(4S0)ns 3S0; 2p3(4S0)nd 3D0; 2p3(2D0)ns′ 3D0;2p3(2D0)nd′ 3S0; 2p3(2D0)nd′ 3P0; 2p3(2D0)nd′ 3D0;2p3(2P0)ns′′ 3P0; 2p3(2P0)nd′′ 3P0; and 2p3(2P0)nd′′ 3D0.Measurement and classification of these lines are given. Most of the atomic-energy levels involved were not previously known. The new O2 bands are a progression of 10 members in the 835–900-Å region. A definite assignment cannot be made at present, but the lower state is either the a 1Δg or the b 1Σg+ metastable state, with the former regarded as most likely. The spectra were observed both in a flowing microwave discharge and in the region downstream from this discharge.