Molecular constants for the ν=0, b1Σg+ excited state of O2:: Improved values derived from measurements of the oxygen A-band using intracavity laser spectroscopy

High-resolution intracavity laser spectroscopy (ILS) absorption measurements have been made on the b-X oxygen electronic transition (the A-band) which has bandheads occurring in the region of 13 165 cm(-1). The positions of the lines were determined to an accuracy that is based on calibration with It absorption lines using the Laboratoire Aime Cotton (Orsay) Atlas as reference. Based on the ILS measurements and the more accurately determined positions given by L. R. Brown and C. Plymate (J. Mol. Spectrpsc. 199, 166-179 (2000)) and with the (3)Sigma (-)(g) ground state molecular constants fixed at the values determined by G. Rouille et al. (J. Mol. Spectrosc. 154, 372-382 (1992)), the following values (in cm(-1)) were found for the molecular constants: T-0 = 13122.2524(1); B-0 = 1.391244(2); D-0 = 5.352(4) x 10(-6); and H-0 1.2(2) x 10(-11). These results are compared with values derived from fits of the line positions listed in several other studies of this transition. (C) 2001 Academic Press.