［Mg(NH2)2］n(n=1—5)团簇的密度泛函理论研究

用密度泛函理论的杂化密度泛函B3LYP方法在6-31G^*基组水平上对［Mg(NH₂)₂］_n(n=1—5)团簇各种可能的构型进行几何结构优化，预测了各团簇的最稳定结构.对最稳定结构的振动特性、成键特性、电荷特性等进行了理论研究.结果表明：团簇易形成链状结构，Mg—N键长为0.190—0.234 nm，N—H键长为0.101—0.103 nm，H—N—H键角为100.2°—107.5°；团簇中M 关键词： 2)₂］_n(n=1—5)团簇')" href="#">［Mg(NH₂)₂］_n(n=1—5)团簇 密度泛函理论 结构与性质 储氢材料

Density functional theory study of ［Mg(NH2)2］n(n=1—5) clusters

Possible geometrical structures and relative stabilities of ［Mg(NH₂)₂］_n(n=1—5) clusters are studied by using the hybrid density functional theory (B3LYP) with 6-31G^* basis sets. For the most stable isomers, the electronic structure, vibrational properties, bond properties and ionization potentials are analyzed. The calculated results show the following tendencies: the Mg and N atom are bonded with each other to form catenulate structures. The bond lengths for ［Mg(NH₂)₂］_n (n=1—5) clusters are about 0.190—0.234nm for Mg—N, and 0.101—0.103 nm for the N—H bonds, the bond angles of H—N—H are about 100.2°—107.5°. The population analysis suggests that the natural charge of N atoms are about -1.551e—-1.651e, that of Mg atoms are about 1.585e—1.615e, that of H atoms are about 0.369e—0.403e, and that of—NH₂ are about -0.784e—-0.845e, and the bonds between Mg and —NH₂ have strong ionicity. The comparative study of structures and spectra of clusters and crystal show that —NH₂ keeps the integrity in the crystal and in clusters.