Infrared spectrum of monoisotopic germyl bromide in the 5 μm region

Abstract

The Fourier transform infrared spectrum of monoisotopic H 3 74Ge 79Br has been recorded at 3 × 10 −3 cm −1 resolution in the 2000–2250 cm −1 region. The rotational structure of the ν 1 and ν 4 fundamental bands and of the ( ν 1 + ν 3) − ν 3 and ( ν 3 + ν 4) − ν 3 hot bands has been thoroughly investigated. The available data consisted of more than 6200 transitions of the fundamentals and 500 transitions of the hot bands. With these data, the band origins and rotational constants of the v 1 = 1, v 4 = 1, v 1 = v 3 = 1, and v 3 = v 4 = 1 states have been accurately determined. Lower state combination difference fits have been performed to determine the rotational constants of the ground and v 3 = 1 state. The Coriolis resonance between ν 1 and ν 4 and the l-doubling in ν 4 have been studied. A local resonance affecting the K.Δ K = 10 subband of ν 4 around J = 57 has been detected and the cause of the perturbation has been tentatively identified as the v 3 = 1, v 5 = 2 +2 state. In general, the accuracy of the parameters determined in this work is one order of magnitude better than in the previous works. Three weak hot bands, originating from the levels v 3 = 2 and v 6 = 1, have also been detected and anharmonicity parameters evaluated.