Analysis of the ν₁+ν₃ band of T₂¹⁶O and the ν ₁ + ν ₃ and 2ν₂ + ν₃ bands of DT¹⁶O

We present the ν1+ν3 band of T216O and the ν1+ν3 and 2ν2+ν3 bands of DT16O that have been analysed for the first time using high-resolution infrared spectra of tritiated water vapour. The spectrum for T216O has been recorded from a custom-built light-pipe cell at room temperature using a Bruker 125HR Fourier-transform spectrometer at a resolution of 0.025cm−1. For the DT16O species, an optimised version of the optical cell with 10 times larger maximum activity with regard to previous studies has been employed. For the ν1+ν3 band of T216O, we report 206 new experimental line positions in the range from 4415 to 4645cm−1. In the range of 4780–5175cm−1, 356 new experimental line positions of the DT16O have been assigned for the ν1+ν3 band and 161 line positions for the 2ν2+ν3 band. The analysis agrees with previous observations showing a systematic shift of the individual line positions compared to the variationally calculated line positions from the Tomsk database. This shift is depending on the rotational quantum number Ka. For each band, the assigned lines were used to determine the spectroscopic constants of the A-reduced Watson-type Hamiltonian.