title: Density functional theory study on structure and stability of BeBn+clusters.
abstract: BACKGROUND
  Boride compounds hold promise for broad applications in the field of optoelectronics due to their high-temperature resistant, corrosion resistant and antioxidant properties. In order to reveal the formation mechanism of alkali and alkaline earth metal doped boron clusters, theoretical studies of these systems are required.
  
  
  METHODS
  All the possible geometrical structures of BeBn+clusters (n = 1-8) were optimized at the B3LYP/6-311+G(d) level; the harmonic vibration frequencies were obtained to examine the true stability and give the zero-point vibration energy at that theoretical level. The single point energies of all the structures were computed at the CCSD(T)/aug-cc-pVDZ level. For the most stable structures, the average binding energy (Eb), the fragmentation energy (EF) and second-order difference of total energy (Δ2E) were used to evaluate the relative stability of clusters.
  
  
  RESULTS
  Most of the BeBn+clusters are planar in structure; the B atoms tend to aggregate to form a boron ring, and the coordinating Be atoms are on the periphery of the clusters. The fragmentation energy and second-order difference of total energy show that there is an obvious odd-even alteration as n increases, and local-maxima when n is odd.
  
  
  CONCLUSIONS
  A systematic theoretical investigation on the geometries, stabilities and electronic properties of BeBn+clusters has been carried out where n = 1-8. The results provide a useful reference for understanding the formation mechanism and stability of these clusters, as well as guidance for finding larger size clusters.
authors.affiliation: School of Chemistry and Chemical Engineering, Xuchang University of China, No. 88 Bayi Road, Xuchang, Henan Province, 461000, P.R. China.
authors.forename: Chunhui
authors.identifier: http://orcid.org/0000-0002-2102-2829
authors.initials: C
authors.lastname: Liu
authors.affiliation: School of Chemistry and Chemical Engineering, Xuchang University of China, No. 88 Bayi Road, Xuchang, Henan Province, 461000, P.R. China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Si
authors.affiliation: School of Chemistry and Chemical Engineering, Xuchang University of China, No. 88 Bayi Road, Xuchang, Henan Province, 461000, P.R. China.
authors.forename: Peilin
authors.initials: P
authors.lastname: Han
authors.affiliation: The College of Chemistry and Molecular Engineering, Center of Computational Chemistry, Zhengzhou University of China, No. 100 Science Road, Zhengzhou, Henan Province, 450001, P.R. China.
authors.forename: Mingsheng
authors.initials: M
authors.lastname: Tang