Theoretical Study Of The Binary Be-Cu Clusters

The geometrical structures, electronic properties and relative stabilities of smallbimetallic Be_nCu_m(n+m=2-7) clusters have been systematically investigated byusing a density functional method at the B3PW91level. In the most stable structuresof Be_nCu_m, the Be atoms tend to gather together and construct similar configurationsto those of pure Be_nclusters. Meanwhile, there is a tendency for Cu atoms tosegregate toward the Be_ncluster surface. The successive binding energies, cohesiveenergies, second difference of energies, the highest occupied-lowest unoccupiedmolecular orbital energy gaps and chemical hardness of Be_nCu_mare also investigated.All of them demonstrate that the clusters with even number of copper atoms presentrelatively higher stabilities. The natural population analyses on the Be_nCu_mclustersreveal that, the charge transfers from Be to Cu when the average coordinationnumbers (Nc) of Be atom is less than3, whereas the charge-transferring directionreverses when Nc(Be) increases.