TY - JOUR
T1 - Structure and vibrational spectra of low-energy silicon clusters
AU - Sieck, A.
AU - Porezag, D.
AU - Frauenheim, Th
AU - Pederson, M. R.
AU - Jackson, K.
PY - 1997
Y1 - 1997
N2 - We have identified low-energy structures of silicon clusters with 9 to 14 atoms using a nonorthogonal tight-binding method (TB) based on density-functional theory (DF). We have further investigated the resulting structures with an accurate all-electron first-principles technique. The results for cohesive energies, cluster geometries, and highest occupied to lowest unoccupied molecular orbital (HOMO-LUMO) gaps show an overall good agreement between DF-TB and self-consistent-field (SCF) DF theory. For Si[Formula Presented] and Si[Formula Presented] we have found equilibrium structures, whereas for Si[Formula Presented] Si[Formula Presented] and Si[Formula Presented] we present clusters with energies close to that of the corresponding ground-state structure recently proposed in the literature. The bonding scheme of clusters in this size range is different from the bulk tetrahedral symmetry. The most stable structures, characterized by low energies and large HOMO-LUMO gaps, have similar common subunits. To aid in their experimental identification, we have computed the full vibrational spectra of the structures, along with the Raman activities, IR intensities, and static polarizabilities, using SCF-DF theory within the local-density approximation (LDA). This method has already been successfully applied to the determination of Raman and IR spectra of silicon clusters with 3–8, 10, 13, 20, and 21 atoms.
AB - We have identified low-energy structures of silicon clusters with 9 to 14 atoms using a nonorthogonal tight-binding method (TB) based on density-functional theory (DF). We have further investigated the resulting structures with an accurate all-electron first-principles technique. The results for cohesive energies, cluster geometries, and highest occupied to lowest unoccupied molecular orbital (HOMO-LUMO) gaps show an overall good agreement between DF-TB and self-consistent-field (SCF) DF theory. For Si[Formula Presented] and Si[Formula Presented] we have found equilibrium structures, whereas for Si[Formula Presented] Si[Formula Presented] and Si[Formula Presented] we present clusters with energies close to that of the corresponding ground-state structure recently proposed in the literature. The bonding scheme of clusters in this size range is different from the bulk tetrahedral symmetry. The most stable structures, characterized by low energies and large HOMO-LUMO gaps, have similar common subunits. To aid in their experimental identification, we have computed the full vibrational spectra of the structures, along with the Raman activities, IR intensities, and static polarizabilities, using SCF-DF theory within the local-density approximation (LDA). This method has already been successfully applied to the determination of Raman and IR spectra of silicon clusters with 3–8, 10, 13, 20, and 21 atoms.
UR - http://www.scopus.com/inward/record.url?scp=0031373734&partnerID=8YFLogxK
U2 - 10.1103/PhysRevA.56.4890
DO - 10.1103/PhysRevA.56.4890
M3 - Article
AN - SCOPUS:0031373734
VL - 56
SP - 4890
EP - 4898
JO - Physical Review A - Atomic, Molecular, and Optical Physics
JF - Physical Review A - Atomic, Molecular, and Optical Physics
SN - 1050-2947
IS - 6
ER -