Density Functional Theory Study on the Structures and Properties of(Mg_3N_2)_n(n=1～4) Clusters

Possible geometrical structures and relative stabilities of(Mg3N2)n(n=1～4) clusters are studied by using the hybrid density functional theory(B3LYP) with 6-31G* basis sets.For the most stable isomers of(Mg3N2)n(n=1～4) clusters,the electronic structure,vibrational properties,bonds properties,relative stabilities are analyzed.The following tendencies shown in the calculated results: the Mg and N atoms bonded each other to form a cage structure of the most stable isomers for n(n=1～4) clusters;the coordination numbers of N atoms are usually 3 or 4;Mg-N bonds are favorable in energy and the bond lengths are about 0.194～0.218 nm for Mg-N and 0.262～0.298 nm for Mg-Mg;the population analysis suggests the average natural charge of N atoms is about-2.06 e and that of Mg atoms about +1.37 e;the dynamic stability of(Mg3N2)2 cluster is higher than that of other clusters.