High-resolution IR spectrum of AsH2D: Ro-vibrational analysis of the bending triad bands ν3, ν4, and ν6

The infrared spectrum of the AsH2D molecule has been measured in the region of the three bending fundamental bands on a Fourier transform spectrometer with a resolution of 0.0024 cm−1 and analyzed for the first time. More than 7500 normally allowed and in addition about 600 forbidden, but perturbation-activated transitions with Jmax=21, Kamax=20 and Kcmax=21 have been assigned to the bands ν3, ν4, and ν6. The measured transition wavenumbers were used to determine 1047 upper energy values. These energies were fitted with a Watson-type Hamiltonian in A reduction and IIIl representation taking into account resonance interactions between all three bending states, (001000), (000100), and (000001) and led to a physically meaningful set of 25 diagonal and 52 resonance spectroscopic parameters. These reproduce the experimental energies with an rms deviation of 0.00021 cm−1, which is close to the experimental uncertainty.