Study of highly excited ro-vibrational states of S18O2 from “hot” transitions: The bands ν1+ν2+ν3−ν2, 2ν1+ν2−ν2, and 2ν2+ν3−ν2

•High resolution analysis of S1832O2 hot bands.•Resonance interactions.•Determination of spectroscopic parameters.

Transitions belonging to the three “hot” bands of the S18O2 molecule, ν1+ν2+ν3−ν2 (621 transitions with the values of quantum numbers Jmax=49 and Kamax=14), 2ν1+ν2−ν2 (332 transitions with Jmax=42 and Kamax=12) and 2ν2+ν3−ν2 (15 transitions with Jmax=14 and Ka=8 and 9), were assigned in the spectral 2100-2700 cm−1 region. This enabled for the first time to get high accurate values of 388, 185 and 13 ro-vibrational energies for the highly excited vibrational states (111), (210) and (021), respectively. A weighted fit analysis using the obtained ro-vibrational energies allowed us to generate a set of 20 fitted parameters which reproduce the initial 586 energy values (about 970 assigned experimental transitions) with the drms deviations of 1.9×10−4cm−1, 2.8×10−4 cm−1 and 2.5×10−4 cm−1 for the states (111), (210) and (021).