CW-Cavity Ring Down spectroscopy of 18O3. Part 1: Experiment and analysis of the 6200–6400 cm−1 spectral region

Abstract The absorption spectrum of the 18 O 3 isotopologue of ozone has been recorded in the 6200–6400 cm −1 region by high sensitivity CW-Cavity Ring Down Spectroscopy. The spectrum is dominated by the 2ν 1  + 5ν 3 and 2ν 1  + 3ν 2  + 3ν 3 bands at 6270.6 and 6392.2 cm −1 , respectively which were treated independently. The rovibrational analysis of the 2ν 1  + 5ν 3 band has evidenced that the (2 0 5) upper state is perturbed by Coriolis resonance interactions with the (0 1 6), (3 0 4) and (3 5 0) states. A total of 659, 89, 131 and 5 transitions were assigned to the 2ν 1  + 5ν 3 , ν 2  + 6ν 3 , 3ν 1  + 4ν 3 and 3ν 1  + 5ν 2 bands, respectively. In the case of the 2ν 1  + 3ν 2  + 3ν 3 band, 344 transitions were assigned. Some of them were found perturbed by a Coriolis interaction of the (2 3 3) state with the (5 2 0) state. Overall, 681 energy levels were derived from the analysis of the 2ν 1  + 5ν 3 and 2ν 1  + 3ν 2  + 3ν 3 band systems. In both cases, a suitable effective Hamiltonian was elaborated, allowing accounting satisfactorily for the retrieved rovibrational energy levels. In addition, dipole transition moment parameters were determined by a least-squares fit to the measured line intensities. The effective Hamiltonian and transition moment operator parameters were used to generate a list of 1619 transitions given as Supplementary material .