High resolution study of the rotational structure of doubly excited vibrational states of ³²S¹⁶O¹⁸O: The first analysis of the 2ν₁, ν₁+ν₃, and 2ν₃ bands

The high resolution infrared spectra of the ³²S¹⁶O¹⁸O molecule were recorded with a Bruker IFS 120 HR Fourier transform interferometer for the first time in the region of 1800–2800 cm⁻¹ where the bands 2ν₁, ν₁+ν₃, and 2ν₃ are located. About 3970, 2960 and 3450 transitions were assigned in the experimental spectra with the maximum values of quantum numbers J^max./K_a ^max. equal to 59/20, 68/25, and 43/18 to the bands 2ν₁, ν₁+ν₃, and 2ν₃, respectively. The subsequent weighted fit of experimentally assigned transitions was made with the Hamiltonian model which takes into account the resonance interactions between the studied vibrational states. As the result, a set of 39 fitted parameters was obtained which reproduces the initial 3213 ro-vibrational energy values obtained from the assigned transitions with the d_rms=2.4×10⁻⁴cm⁻¹.