High-resolution infrared spectra of 18O 16O 18O ozone isotopomer in the range 900–5000 cm −1: line positions

Abstract

Continuing the systematic study of ozone high-resolution infrared spectra, we present in this paper the measurements and analyses of line positions for the 18O 16O 18O isotopomer. In the range 900–5000 cm −1, corresponding to the observed spectra, 15 bands are analysed: ν 1, ν 3, ν 2+ ν 3, ν 1+ ν 2, 2 ν 3, ν 1+ ν 3, 2 ν 1, ν 2+2 ν 3, ν 1+ ν 2+ ν 3, 3 ν 3, 2 ν 1+ ν 3, ν 2+3 ν 3, ν 1+3 ν 3, ν 1+ ν 2+3 ν 3, and 5 ν 3. As in the case of 16O 3, 18O 3, and 16O 18O 16O, the analysis of these bands is performed using effective rovibrational Hamiltonians for nine polyads of interacting upper vibrational states. To correctly reproduce all observed transitions, we have to account for resonance perturbations due to 13 “Dark” states: (0 3 0), (0 4 0), (2 1 0), (0 3 1), (1 0 2), (0 4 1), (1 1 2), (3 1 0), (0 3 2), (0 0 4), (3 2 0), (0 1 4), and (0 4 2). We present the range of observed transitions, the results for spectroscopic parameters (vibrational energy levels, rotational and centrifugal distortion constants, and resonance coupling parameters), as well as the statistics for rovibrational energy levels, calculations and measurements. A comparison of observed band centres with those predicted from an isotopically invariant potential function is discussed. The RMS deviation between predicted and directly observed band centres is ≈0.03 cm −1 up to 3000 and ≈0.25 cm −1 for all 16 bands up to 5000 cm −1.