2017ApJS..228...15M

Accurate, experimental rovibronic energy levels, with associated labels and uncertainties, are reported for 11 low-lying electronic states of the diatomic ⁴⁸Ti¹⁶O molecule, determined using the Marvel (Measured Active Rotational-Vibrational Energy Levels) algorithm. All levels are based on lines corresponding to critically reviewed and validated high-resolution experimental spectra taken from 24 literature sources. The transition data are in the 2-22,160 cm^–1 region. Out of the 49,679 measured transitions, 43,885 are triplet-triplet, 5710 are singlet-singlet, and 84 are triplet-singlet transitions. A careful analysis of the resulting experimental spectroscopic network (SN) allows 48,590 transitions to be validated. The transitions determine 93 vibrational band origins of ⁴⁸Ti¹⁶O, including 71 triplet and 22 singlet ones. There are 276 (73) triplet-triplet (singlet-singlet) band-heads derived from Marvel experimental energies, 123(38) of which have never been assigned in low- or high-resolution experiments. The highest J value, where J stands for the total angular momentum, for which an energy level is validated is 163. The number of experimentally derived triplet and singlet ⁴⁸Ti¹⁶O rovibrational energy levels is 8682 and 1882, respectively. The lists of validated lines and levels for ⁴⁸Ti¹⁶O are deposited in the supporting information to this paper.