Critical Evaluation of Measured Transition Frequencies of 16OD Molecule in X2Π State Using the Ritz Principle

Determining the spectrum structure, i.e., finding the empirical energy levels of a molecule, is a relevant and important task of spectroscopy. For deuterated hydroxyl (OD), such information is absent in known spectroscopic databases. Therefore, empirical energy levels of 16OD were determined in this work. For the first time, the critical analysis of 3138 available experimental frequencies of rotational and vibrational-rotational transitions of 16OD molecule in X2П ground electronic state was performed using the Ritz combination principle. Transitions with hyperfine splitting were not considered. The transition frequencies weighted in accordance with the experimental uncertanties were processed by the RITZ program code. The analysis of the dimensionless weighted deviations enabled us to exclude from the consideration the frequencies with the weighted deviation higher than four. The resulting set of 2984 transition frequencies made possible processing with a standard deviation of 1.24. As a result of critical evaluation, a set of 864 empirical RITZ energy levels was obtained with an appropriate uncertainty for each level for the first time. The found empirical RITZ energy levels were compared with known literature data.