Abstract: Possible geometrical structures and relative stability of (MgB₂)_n(n=1~3) clusters are studied with a hybrid density functional theory(B3LYP) with 6-31G^* basis sets.For the stablest isomers of (MgB₂)_n(n=1~3) clusters,the electronic structure,vibrational property,bond,ionization potential,polarizability and hyperpolarizability are analyzed. Most of the optimized (MgB₂)_n(n=1~3) clusters are planar structures and the B-B and B-Mg bonds coexist,while the Mg-Mg bonds are infrequent.The bond lengths of B-B and Mg-B are 0.153~0.182 nm and 0.218~0.231 nm,respectively. Several negative B atoms form an electronegative center and other B and Mg atoms with positive charge are located at the apex of the cluster.The natural charges of Mg atom and B atom are +0.559e~+0.920e and -0.724e~+0.197e,respectively.

Key words: (MgB₂)_n(n=1~3) clusters, density functional theory, structure and properties