DFT Study of Geometries and Stability of B_n Clusters (n=2-8)

摘要

With density functional theory (DFT), the structures and stability of B_nclusters with n=2-8 have been studied. Byusing the all electron basis, all the geometries have been globally optimized without any symmetry constraint. It is foundthat all the small B_n (n=2-8) clusters prefer to form planar structures with sp~2bonds, which are in good agreement withothers' related studies. B_nand B_nare also compared. In contrast with the neutral B_nclusters, although B-B distances inB_n have slight differences, but addition of one electron does not change their structures significantly. As for energies, allthe anions are lying lower than their corresponding neutral clusters. In addition, calculations of energetic and electronicproperties for all the neutral clusters have been presented. Both of these two properties show that in B_n(n=2-8),B_3andB_5are more stable than others. Vibrational spectra ofB_n(n=3-8) clusters have also been discussed. In each spectrum,intensity peaks which are associated with the vibration of boron clusters related to B-B bond stretching can be observedand they are highest. However, among all the B_n clusters, such peaks of B_3andB_5show lower intensity than others. Thisresults suggest that B_3andB_5are relatively more stable, which further demonstrates the conclusion above.