The uv spectrum of 18OD

Abstract

The combined high-resolution ultraviolet (uv) absorption spectrum of 16OD and 18OD was obtained. State selective measurements of the transitions from the electronic ground state to the first excited electronic state, A ̃ 2 Σ + ← X ̃ 2 Π , in the 0-0 vibronic band were performed by means of a narrow bandwidth dye laser system. Evaluation of these transition frequencies in wave-numbers yielded molecular constants as well as rotational term values for each of the isotopic species. A computer program based on a linearized least-squares procedure was used to determine the molecular constants and term values. The term value formulas which were employed for this purpose, take into account the Λ splitting and the centrifugal distortion of the diatomic species. The transitions, recalculated from the semiempirically determined term values agree with the measured absorption lines to better than 0.1 cm −1. The following molecular constants are reported: B, D, H, the rotational constants of the 2Π and 2Σ + states; O 0, P 0, Q 0, the constants of the Λ splitting of the 2Π state; A and A 1; the constants of the spin-orbit coupling of the 2Π state; and γ 0, the constant of the p doubling of the 2Σ + state. Futhermore, term values up to J″ and J′ of 25.5 and the corresponding uv transitions are given.