Absorption spectrum of the NO molecule. IX. The structure of the f complexes, the ionization potential of NO, and the quadrupole moment of NO+

Abstract

The 0–0 bands at 1474 Å and 1422 Å of the first two members of the nf–X2Π Rydberg series of NO have been observed under high resolution in the absorption spectrum of cold nitric oxide gas. They show an abnormal rotational structure which has been analyzed with the help of a computer program. The uncoupling of the angular momentum l = 3 of the f electron in the rotating molecule is discussed theoretically, including the effect of electron spin and interaction with the molecular core. The connection between the electronic energies TΛ of the f complex in the nonrotating molecule and the electronic energies [Formula: see text] in the rapidly rotating molecule is given. From the analysis a precise value of the ionization potential of NO is obtained, viz. T∞ = 9.2639 ± 0.0006 eV, and the quadrupole moment of the molecular ion NO+ is determined to be Qzz = +(0.79 ± 0.06) 10−26 e.s.u. cm2. The "atomic" and the "molecular" properties of a highly excited molecular Rydberg electron are discussed.