Absorption Spectrum of the No Molecule: Vi. Band Structures Below 1 600 Å, Rydberg States C2π, D2σ+, K2π, M2σ+, S2σ+, Non-Rydberg States B2π, L2π and Their Interactions

The study of the absorption spectrum of the NO molecule has been continued on plates taken in the fourth order of a 10.5-m vacuum spectrograph. The spectra of 14N16O, 15N16O, 14N18O, and 15N18O gases, each kept at liquid-oxygen temperature, were photographed separately. Rotational analyses were carried out for many bands observed below 1 600 Å. Constants for levels of the Rydberg complexes 3p, 4s, 4p, and 5s have been derived. These levels include ν = 5 and ν = 6 of the C2Π state, levels that interact with the levels ν = 21 and 24 respectively of the configurationally different B2Π state. It is shown that the vibrational levels, now well established above the energy where the potential curves of the C and B states cross, are to be attributed to "crossing" curves.The level ν = 4 of the L2Π state, which was discerned in the spectra of the heavier isotopes only, coincides in 14N16O with the level ν = 6 of C2Π and produces a strong three-level perturbation. The level, perturbed in this way, has the appearance of a separate electronic state in 14N16O and at one time was so identified.Many interaction energies are determined, and the new systems of "deper-turbed" levels are thoroughly discussed.