Density functional theory study on the beryllium clusters doped with silicon atom

Abstract

An all-electron calculation on BenSi (n = 1–12) clusters has been performed by using density functional theory with the generalized gradient approximation at the PW91 level. The results reveal that the lowest energy geometries of BenSi (n = 1–12) clusters may be generated by substituting a Si atom for one Be atom of the Ben+1 clusters. In addition, Si atom tends to occupy external locations of main Ben clusters and bonds with multiple Be atoms in the BenSi (n > 2) clusters. The average binding energy of BenSi clusters is higher than that of pure Ben+1 clusters, indicating that the doped of the Si atom enhances the cluster's binding force. Compared with pure Ben+1 clusters, the HOMO-LUMO GAP of Be7Si, Be8Si, and Be10Si clusters increase while the HLG of other BenSi clusters(n = 1–3,5,9,11,12) decreas. The vertical ionization potential and vertical electron affinities curves of clusters have the same general trend. The VIP of the cluster decreases gradually while the VEA increases gradually. The doping of the Si atom greatly influences the stability of pure Ben clusters, and the analysis of energy and electronic properties of BenSi clusters reveals that the Be3Si cluster is the magic number structure in the system.