Hyperfine Splittings in the Optical Spectrum of NbO⁺

Abstract

AN electronic system of the molecule NbO⁺ has been analysed and has been shown to be an unparalleled example of the coupling of electron and nuclear spins described as case a_β; that is, one in which the electronic momenta are tightly coupled to the internuclear axis while the nuclear spin is quantized in the laboratory frame^1,2 (rather than in the internal internuclear axis system). The system has been observed in emission in the red region of the optical spectrum using a resolving power which is theoretically about 500,000—that is, energy differences of about 0.035 cm^-1 can be observed. It consists of only a 0,0 sequence and has been analysed as ³Φ→³Δ. The three 0,0 sub-bands have been observed as shown in Table 1.