Ab initio molecular orbital calculations of the energetic,structural, vibrational and electronic properties of some hydrogen bonded complexes of water,ammonia and hydroxylamine

Recently published results of some ab initio molecular orbital calculations on 10 hydrogen bonded homodimers and heterodimers of water, ammonia and hydroxylamine have been analysed. The properties discussed include the interaction energies, the structural parameters of the hydrogen bonded fragments, RAH⋯B, the vibrational properties (wavenumbers of the bonded AH-stretching and RAH-bending vibrational modes, and their shifts, and the wavenumbers of the highest frequency intermolecular modes of the complexes), and the atomic polar tensors, their invariants, and the Mulliken charges of the bonded hydrogen atoms. It is concluded that such complexes are stabilized by hydrogen bonds of the OH⋯N, OH⋯O and NH⋯N type, listed in decreasing order of strength. The complexes tend to form preferentially open (more or less linear) structures, followed by large cyclic structures, in which ring strain is minimized, and finally small cyclic structures, in which ring strain is more important.