title: The structure and energetics of (GaAs)n, (GaAs)n(-), and (GaAs)n+ (n=2-15).
abstract: Electronic and geometrical structures of neutral, negatively, and positively charged (GaAs)n clusters are computed using density functional theory with generalized gradient approximation. All-electron computations are performed on (GaAs)2-(GaAs)9 while effective core potentials (ECPs) are used for (GaAs)9-(GaAs)15. Calibration calculations on GaAs and (GaAs)9 species support the use of the ECP for the larger clusters. The ground-state geometries of (GaAs)n(-) and/or (GaAs)n+ are different from the corresponding neutral ground-state geometry, except for n=7, 9, 12, 14, and 15, where the neutral and ions have similar structures. Beginning with n=6, all atoms are three coordinate, except for (GaAs)10+ and (GaAs)13+. For the larger species, there is a competition between fullerenes built from hexagons and rhombi and geometrical configurations where Ga-Ga and As-As bonds are formed, which results in the formation of pentagons. As expected, the static polarizability varies in the order of anion>neutral>cation, but the values are rather similar for all three charge states. The thermodynamic stability for the loss of GaAs is reported.
authors.affiliation: Environmental Sciences Institute, Florida A&M University, Tallahassee, Florida 32307, USA. gennady.gutsev@famu.edu
authors.forename: G L
authors.initials: GL
authors.lastname: Gutsev
authors.forename: E
authors.initials: E
authors.lastname: Johnson
authors.forename: M D
authors.initials: MD
authors.lastname: Mochena
authors.forename: C W
authors.initials: CW
authors.lastname: Bauschlicher