High-resolution infrared study of the ν1 and ν3 bands, and the equilibrium structure of AsD3

The infrared spectrum of the AsD3 molecule has been measured in the region of the stretching fundamental bands on a Fourier transform spectrometer with a resolution of 0.0027 cm−1 and analyzed for the first time. More than 3300 normally allowed and in addition more than 900 forbidden, but perturbation-allowed transitions with Jmaxupper=28 have been assigned to the bands ν1 and ν3. An effective Hamiltonian was used which takes into account the resonance interactions between the states (1000) and (0010). A set of 50 (26 diagonal and 24 resonance) refined spectroscopic parameters was obtained from the fit which reproduces the 1229 initial ‘experimental’ upper state ro-vibrational energies with an rms deviation of 0.00024 cm−1. The transition moment ratio |μ1:μ3| was determined to be 1.2±0.05, and the intensity perturbation μ1ξ13yμ3 found to be negative. The equilibrium values of the bond length rAs–De=1.51130(11)Å and interbond angle αD–As–De=92.0775(40)˚ were determined from the values of the rotational parameters of the ground state and the four fundamental bands.