Wavelength measurement and analysis of the Schumann-Runge absorption bands of 18O 2 in the region 175–205 nm

Abstract

High-resolution absorption spectra of 18O 2 have been photographed, at 300 and 79 K, throughout the region 175–205 nm, in the first order of a 2400 lines/mm grating in a 6.65-m vacuum spectrograph at a dispersion of 0.06 nm/mm. Precise wavelength measurements and rotational analyses of the Schumann-Runge bands (2, 0)-(19, 0) have been completed. Spectroscopic constants of the B 3Σ u − state of 18O 2 for 2≤ v ≤ 18 have been determined. Rotational perturbations are observed in the (18, 0) and (19, 0) bands. Values of the spin-spin and spin-rotation constants have been obtained by interpolation for the levels v = 2−10 and 2−7, 10, respectively, which correspond to bands with unresolved triplet structure.