Jucai Yang

Structures and Electronic Properties of Beryllium Atom Encapsulated in Sin(0,−1) (n = 2−10) Clusters

The equilibrium geometries and energies of neutral BeSi(n) (n = 2-10) species and their anions have been studied at the highest level of Gaussian-3 (G3) theory. The results reveal that the ground-state structures of these clusters are Be-encapsulated in silicon cages with n >or= 8. The reliable adiabatic electron affinities of BeSi(n) have been predicted to be 1.68 eV for BeSi(2), 1.87 eV for BeSi(3), 2.33 eV for BeSi(4), 2.29 eV for BeSi(5), 2.11 eV for BeSi(6), 2.37 eV for BeSi(7), 2.95 eV for BeSi(8), 2.74 eV for BeSi(9), and 1.92 eV for BeSi(10). The dissociation energies of Be atom from BeSi(n), Si atom from BeSi(n), and Si atom from Si(n) clusters have also been calculated, respectively, to examine relative stabilities. The trend of stability of BeSi(n) changed with n is converse to that of Si(n) when n <or= 7. From n >or= 8, the encapsulated Be atom in silicon cages not only results in an identical trend for stability of BeSi(n) and Si(n) but also improves the stability of Si(n) clusters.

EQUILIBRIUM GEOMETRIES AND ELECTRONIC STRUCTURE OF SMALL SILICON MONOHYDRIDES CLUSTERS

The geometries and energies of small silicon monohydride clusters (Si2H–Si10H) have been systematically investigated by density functional theory (DFT) scheme with DZP++ basis sets. Several possible geometric arrangements and electronic states have been considered for each cluster. The results on Si2H–Si4H are in good accordance with previous ab initio calculation. The geometry of ground state of Si2H is found to be a bridged C2v structure, and Si3H to be a bridged C2v, while Si4H a non-bridged Cs symmetry with 2A′ state. The non-bridged geometries of ground state of Si5H–Si10H have been found to be corresponding to C2v(2B1), C2v(2B1), C5v(2A1), Cs(2A′′) (have two types), C1 (not symmetry), and Cs(2A′), respectively. The results on Si5H, Si6H, Si8H and Si9H are different from previous calculations. Compared silicon clusters (Sin) with silicon monohydrides (SinH) clusters, the addition of a single hydrogen atom cannot cause great changes in the ground state geometries of Si2, Si3, Si4, Si7, Si9, and Si10 clusters, while in the ground state geometries of Si5, Si6 and Si8 clusters the change is great. The dissociation energies calculated indicates that Si4H, Si7H, and Si10H clusters are less stable than others.