Complete RITZ Set of Ro-Vibrational Energy Levels of ¹⁶O₃ Deduced from Experimental Spectra: Critical Analysis of Transition Frequencies in Spectroscopic Databases.

This article presents the most comprehensive empirical determination to date of 28,572 rovibrational energy levels of the electronic ground state of the ozone (^16O_3) molecule, derived from 75,290 experimentally measured spectral transitions spanning 0.3 to 7999 cm^−1. Using a dedicated RITZ computer code based on the fundamental Ritz-Planck-Einstein energy conservation principle, the authors solved an overdetermined system of equations to obtain energy levels with realistic uncertainties and correlation matrices, without relying on approximate Hamiltonian models. The dataset covers 98 vibrational states up to rotational quantum numbers J = 80 and K_a = 29, including 95 cold and 80 hot bands, and achieves root-mean-square deviations as low as 2.6 × 10^−6 cm^−1 for microwave data and 1.8 × 10^−4 cm^−1 for infrared transitions relevant to atmospheric and astrophysical applications. A detailed comparison with the HITRAN2020 spectroscopic database reveals areas where HITRAN line positions and error estimates can be improved, highlighting the value of the RITZ-derived energy levels for refining ozone spectral data used in climate, atmospheric chemistry, and planetary research.