More than 5050 rovibrational transitions were assigned in the very sensitive CW-CRDS O-18(3) spectra in the 5900-7000 cm (1) range leading to the first determination of 14 new vibrational band centres. Three bands correspond to the highest ozone states observed so far under high resolution. The good agreement between predicted and observed centres (rms deviation of 1.1 cm (1)) con. rms the accuracy of the potential function previously determined from O-16(3) data. At this energy range situated similar to 20% below the dissociation energy, the small changes of masses associated with the O-16(3) -> O-18(3) homogeneous isotopic substitution result in irregular isotopic shifts. (C) 2009 Elsevier B.V. All rights reserved.