Theoretical studies of neutral and cationic selenium clusters

Geometries and energetics of both Se-n and Se-n(+) (n less than or equal to 8) clusters are systematically investigated using the methods based on dens ity-functional theory with the local-density approximation and the generali zed gradient approximation. The calculated atomic average binding energies and ionization potentials are in good agreement with the available experime ntal results, which supports the proposed global minima of Se-n (n less tha n or equal to8). For Se-n(+) (n less than or equal to8), the calculated fra gmentation pathways are consistent with the measurements, except for the di ssociation energies of Se-7(+) and Se-8(+). The lowest-energy structures of Se-n(+) in the n less than or equal to8 range are suggested to be the same as those of Se-n in shape.