Theoretical study on the structural, vibrational, and thermodynamic properties of the (Br₂GaN₃)n (n = 1-4) clusters.

The molecular geometries, vibrational properties, and thermodynamic properties of the clusters (Br(2)GaN(3))( n )(n = 1-4) were studied at the B3LYP/6-311+G* level. The optimized clusters (Br(2)GaN(3))( n )(n = 2-4) were all found to possess a cyclic structure consisting of Ga atoms bridged by the α-nitrogen of the azide groups. A discussion of the relationships between the geometrical parameters and the degree of oligomerization n is provided. Features in the IR spectra were assigned by vibrational analysis. Trends in thermodynamic properties with temperature and degree of oligomerization n are discussed. Thermodynamic analysis of the gas-phase reaction showed that the formation of the clusters (Br(2)GaN(3))( n )(n = 2-4) is thermodynamically favorable considering the enthalpies at 298.2 K. The calculated results for the Gibbs free energies were negative, which indicates that the oligomerizations can occur spontaneously at 298.2 K.