CW-Cavity Ring Down Spectroscopy of the ozone molecule in the 5980–6220 cm −1 region

Abstract

The absorption spectrum of ozone, 16O 3, has been recorded in the 5980–6220 cm −1 region by high sensitivity CW-Cavity Ring Down Spectroscopy ( α min ∼ 3 × 10 −10 cm −1). This study extends a first investigation with the same experimental set-up limited to the 6030–6090 cm −1 spectral region [M.-R. De Backer-Barilly, A. Barbe, Vl.G. Tyuterev, D. Romanini, B. Moeskops, A. Campargue, J. Mol. Struct. 780–781 (2006) 225–233] where the analysis of two A-type bands was reported, using FTS spectra for complementary information. The spectral extension of the recordings allows not only to enlarge considerably the observed transitions of these two bands, but more importantly, to assign four new bands: the 3 ν 2 + 4 ν 3,5 ν 1 + ν 2 and ν 1 + 2 ν 2 + 4 ν 3 B-type bands which were considered as dark in our previous report and the 3 ν 1 + 3 ν 2 + ν 3 A-type band. The high mixing of the observed states approaching the dissociation limit, leads to the breakdown of the polyad structure and ambiguities in the vibrational labelling which are discussed. Finally, 1789 transitions were assigned, and a suitable Hamiltonian model allows reproducing correctly the observations for five of the six observed bands. The list of 1004 experimentally determined energy levels is provided. The determined effective Hamiltonian and transition moment operators were used to generate a list of 5338 transitions given as Supplementary Material. It is interesting to note that the d 5 parameter of the effective transition moment is of great importance to account for the observed intensities of the B-type bands.