Extended high resolution analysis of the second triad of D₂ ³²S, D₂ ³³S and D₂ ³⁴S

The high resolution infrared spectra of deuterated hydrogen sulfide D₂ ³²S were recorded with a Bruker IFS 125HR Fourier transform infrared spectrometer and analyzed in the region of 2400–2900 cm⁻¹ where three ν₁+ν₂, ν₂+ν₃ and 3ν₂ interacting bands are located. 4227 transitions with maximum values of the quantum numbers J^max = 28/28/20 and K_a ^max = 18/19/11 were assigned in the experimental spectra to the ν₁+ν₂, ν₂+ν₃ and 3ν₂ bands. On this basis, 399/439/216 upper ro–vibrational energies were obtained for the upper vibrational states (110), (011) and (030) (about 43% more for the number of ro–vibrational energy values and about 63% more for the number of assigned transitions compared to preceding studies). These data were used in the weighted fit of the Watson Hamiltonian parameters. The 97 parameters obtained from the fit reproduce the 1054 initial energy values of three vibrational states used in the fit with the root mean square deviation d_rms=1.97×10⁻⁴ cm⁻¹. The 1215 and 56 transitions belonging to the ν₁+ν₂ and ν₂+ν₃ bands of the D₂ ³⁴S and D₂ ³³S species (410 and 30 upper energy values, respectively) were recorded and analysed for the first time. The ground vibrational state parameters of D₂ ³³S are determined from experimental combination differences.