The structure of AlnNn (n=2–4) clusters: a DFT study

The geometry, harmonic vibrational frequencies and stability of the structural isomers of small aluminum nitride clusters have been investigated using density functional theory. The lowest energy structures are cyclic. The cyclic structures have Dnh symmetry. The caged structure for Al4N4 lies higher in energy than the planar cumulenic monocyclic ring. The Al–N bond dominates the structures for many isomers so that one preferred dissociation channel is loss of the AlN monomer. The properties of the aluminum nitride clusters are similar to those of the BN clusters even though the aluminum atoms have a significantly larger atomic radius.