An ab initio study of the equilibrium geometry and vibrational frequencies of hydrazine

Accurate optimized equilibrium geometries, harmonic frequencies and rotational constants of the gauche conform (C2 symmetry) of hydrazine (N2H4) have been calculated employing a large series of basis sets and several ab initio methods. Our best estimate computed equilibrium geometries are rNN=1.434 Å, rNHi=1.013 Å, rNHo=1.010 Å, θNNHi=111.3°, θNNHo=106.8° and θHiNNHo=89.7°. These predictions were used as reference in the analysis of the experimental and theoretical data, and we expected that the present results could guide future investigations in this direction.