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The infrared absorption spectrum of diimide (N2H2) in the 3.2 μm region has been reexamined at higher resolution than previously, and that of dideuterodiimide (N2D2) at 4.3 μm has been recorded for the first time. The ν5 fundamental (A- and B-type hybrid band) for both isotopic molecules has been analyzed, and a complete set of rotational and centrifugal distortion constants for the ground and ν5 = 1 states have been determined. The rotational constants of the ground states are (cm−1) [Formula: see text] and the following geometrical parameters were obtained for the planar trans-conformation of diimide : [Formula: see text] From the intensity alternation observed in the J structure of N2H2 spectrum, it is concluded that diimide has a totally symmetric ground state.

Spectra of hydrogen sulfide have been recorded between 2150 and 2950 cm−1 with a Fourier transform spectrophotometer at a resolution of 0.01 cm−1. Most of the absorption in this region is due to the 2ν2, ν1, and ν3 bands of H232S, H233S, and H234S observed in natural abundance. A careful analysis of the spectra, combined with recent data on the ground states of the three isotopic species, led to an improved and extended set of rotational energy levels of the (020), (100), and (001) vibrational states of these isotopes. The rovibrational levels have been subjected to a least squares fit, using a Hamiltonian which takes the effects of Coriolis resonance explicitly into account, and precise rotational and coupling parameters have been determined.About 529 individual line intensities have been measured and from them it has been possible to deduce the expansion of the transformed transition moment operators of the three bands 2ν2, ν1, and ν3 and to determine the first derivatives of the dipole moment[Formula: see text]Finally, a complete list of line positions and intensities of natural hydrogen sulfide has been computed which should be of interest for the analysis of infrared spectra of the giant planets and for pollution studies.