DFT Study of Cluster Size-Dependent Structures and Properties of (HClGaN3)n (n=1-6) Clusters

Gallium azides are potential single-source precursors for GaN-based materials. Understanding the size evolution of gallium azides clusters is useful to improve their properties in certain applications by controlling their size. The structures of (HClGaN3)(n) (n = 1-6) clusters are explored using density functional theory method (DFT). The growth behavior indicates that cyclic structures can be easily formed with Ga atoms and N-alpha atoms binding together when n >= 2. The results on geometrical structure parameters of (HClGaN3)(n) (n = 1-6) clusters indicate that our calculated values are in relatively good agreement with availably experimental results. The relative stabilities are discussed by analyzing the second-order energy difference. The IR spectra are obtained and assigned by vibrational analysis. Relationships between thermodynamic properties and temperature/cluster size n are investigated and analyzed, respectively. According to the calculated values of enthalpy and Gibbs free energies, the oligomerizations are thermodynamically favorable at room temperature. These results are helpful to design and synthesize other asymmetric gallium azide clusters.