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

In this work, we provide the most complete to date reference data for 28 572 rovibrational levels of the electronic ground state of the ozone ¹⁶O₃ molecule up to the maximum rotational quantum numbers J = 80, K_a = 29 determined from 75 290 experimental transitions covering the range (0.3–7999) cm⁻¹. These energy levels belong to 98 vibrational states extending up to 96.7% of the first dissociation threshold D₀ of the molecule. The energy determination procedure is based uniquely on the fundamental Ritz-Planck-Einstein energy conservation principle without use of any approximate Hamiltonian models. A dedicated RITZ computer code produces uncertainties and the correlation matrix for all derived energy levels and permits the prediction of confidence intervals for all dipole-allowed transitions among these levels. The rms deviation of the RITZ transitions for microwave experimental data up to the THz range is 2.6 × 10⁻⁶ cm⁻¹. For infrared transitions up to the fundamental and second overtone and combinational bands, including 10 and 5 µm regions important for atmospheric and astrophysical applications, the rms deviation is 1.8 × 10⁻⁴ cm⁻¹. For the entire set of lines, the rms deviation is 5.5 × 10⁻⁴ cm⁻¹ with the overall dimensionless weighted standard deviation of 0.7. Most of the energy level data is original. For the regions above 6000 cm⁻¹, where empirical data have been previously obtained in the literature from CRDS laser measurements, our data agree well with the published values but provide a more realistic uncertainty analysis. Detailed comparisons of the RITZ transitions with the HITRAN2020 database are discussed and related recommendations are suggested.