First high-resolution analysis of the ν1, ν3and ν1+ ν3bands of sulphur dioxide33S16O2

HighlightsHigh-resolution spectra of 33S16O2 have been recorded for the first time in the 8 and 4 µm spectral regions.The ν1, ν3 and ν1 + ν3 bands of the 33S16O2 have been analysed up to very high quantum numbers.Accurate ro-vibrational upper states constants have been determined.