High resolution vacuum ultraviolet absorption spectrum of N2: Perturbations in the and c4(0) 1Πu Rydberg levels

Abstract

High resolution absorption spectra of N2 in the wavelength region 85.73–86.65 nm have been photographed at a reciprocal dispersion of 0.03 nm/mm in the second order of a 2400 line/mm grating by a 6.65 m vacuum spectrograph. The Rydberg transitions [Formula: see text] and [Formula: see text] are analyzed. Gross irregularities in line positions and intensities are interpreted in terms of homogeneous and heterogeneous perturbations among the vibronic levels c4(0), [Formula: see text], b′(18), b(22), b(23), and b(24). A multilevel deperturbation procedure is applied to these levels to produce deperturbed spectroscopic constants. The perturbation matrix elements with the largest values are those of the homogeneous interactions [Formula: see text] and c4(0) × b(23) = 7.3 cm−1, and that of the heterogeneous interaction [Formula: see text]. Term values established for the upper levels c4(0) and [Formula: see text] of the vacuum ultraviolet (VUV) bands are combined with the recent results of Suzuki and Kakimoto for the visible bands c4(0)–a″(0) and [Formula: see text] to obtain term values of the [Formula: see text] level.