X掺杂团簇Bn+1(n=1~11; X=Be, Mn)的密度泛函研究

本文利用密度泛函理论对BnX(n=1~11; X=B, Be, Mn)基态结构、稳定性、电子构型与磁性开展了系统研究. 结果表明: 团簇BnX( n=5~11; X=Be, Mn)中的X原子均位于高配位，BnBe的基态构型为多重度为1或2的低重态；团簇BnX的平均结合能均随尺寸的增大而逐渐增大，n取值相同时，Bn+1团簇的平均结合能最高. HOMO-LOMO能隙结果表明, 掺杂铍原子、锰原子有利于提高纯硼团簇的化学活性；团簇BnBe中的Be原子是电荷的受体，团簇BnMn中Mn原子轨道电子表现出显著的spd杂化；团簇BnX (X=B,Be)中的开壳层结构磁矩主要由2p轨道贡献. 团簇BnMn均为开壳层结构，总磁矩主要由Mn3d轨道贡献. 随着团簇BnMn尺寸的增大，Mn原子的配位数增大，B-Mn平均键长增大，Mn3d轨道磁矩减小而导致团簇的总磁矩减小.

Density functional theory study on X-doped Bn+1 clusters (n=1~11; X=Be,Mn)

The ground state structures, stabilities, electronic configurations and magnetic properties of Bn X clusters(n=1~11; X=B, Be, Mn) have been systematically investigated by density functional theory. The results show that the X atoms are all located with high coordination number in BnX clusters (n=5-11; X=Be, Mn) , The lowest energy structures of BnBe are low spin multiplicity states with multiplicities of 1 or 2. The average binding energies of BnX clusters are increasing with increased size. When n is the same, the cluster Bn+1 has the highest average binding energy. The energy gaps of BnX clusters indicate that the stability of Bn+1 is increased by X-doping (X=Be, Mn). The Be atom is the acceptor of charges in BnBe clusters. The orbital electrons of Mn atoms in BnMn clusters exhibit significant spd hybridization. The magnetic moments of BnX clusters (X = B, Be) with open-shell structures are mainly contributed by 2p orbitals. The electronic structures of BnMn clusters are all Open shell , and the magnetic moment are mainly contributed by Mn3d orbitals. The coordination number of Mn atoms and the average bond lengths of B-Mn increased with size increasing. Accordingly the magnetic moment of BnMn clusters decreased by the reduction of Mn3d orbital magnetic moment.