Theoretical Study Of Structures And Properties Of Oxygen-doped Beryllium Clusters

Clusters are tiny particles composed by a number of atoms,molecules or ions which are held together through physical or chemical forces.Their unique structures,electronic properties,magnetic and optical properties depend on their elemental composition,size and geometry.In this paper,the oxygen-doped beryllium clusters were studied based on the density functional theory.The structure and properties of the clusters with the evolution of the number of oxygen atoms were obtained.The influence of the oxygen atom doping on the pure beryllium clusters and the magic number were studied.According to the study,we found that it has different structural characteristics and properties compared with other doped clusters.On the basis of a large number of initial structures,the lowest-energy structures of the oxygen-doped Be_n（n = 1–12）clusters are obtained by using the 6-311+G（d）basis set at the B3PW91 level.The single-point energy of these structures are obtained by QCISD（T）method,and various energetic and electronic properties of the Be_nO clusters are systematically investigated,which are compared with those of pure Be_n+1 clusters.The evolution of these properties with cluster size shows the unique stability of Be₁₁O.Finally,the electronic structure of the Be₁₁O is analyzed by natural bond orbit（NBO）and electron localization function（ELF）.Be₁₁O can actually be considered as an ionic compound(Be₁₁)²⁺O^2–.On the one hand,O^2– has 8 valence electrons,satisfying the octet rule.On the other hand,the Be₁₁²⁺ moiety has a shell-closed electronic configuration,which renders itself particularly stable.And it is consistent with the conclusion in the cluster electron shell model（CSM）.This study not only provides a new type of nonmetal doped metal clusters,but also stimulates experimental efforts to synthesize and characterize such species in laboratory.