Prediction of the atomic structure and stability for the ensemble of silicon nanoclusters passivated by hydrogen

Abstract

PACS 73.22.-f-Electronic structure of nanoscale materials and related systems PACS 61.46.Bc-Structure of clusters (e.g., metcars; not fragments of crystals; free or loosely aggregated or loosely attached to a substrate) PACS 64.75.Jk-Phase separation and segregation in nanoscale systems Abstract-The total energy and geometry of nanoclusters Si10H2m (m = 0-12) are calculated using evolutionary structure searching and density functional theory. The calculation shows that the arrangement of Si atoms is close to the diamond crystal structure only in the cluster Si10H16, while in others it is unique for each composition. We found that the ensemble of Si10 clusters remains uniform after passivation only if hydrogen concentration corresponds to one of the stable compositions-Si10, Si10H14, Si10H16 Si10H20, or Si10H22. Passivation by an arbitrary amount of hydrogen converts the ensemble into a mixture of the stable clusters having the nearest compositions. In addition there are numerous metastable cluster configurations with energies within ∼ 0.1 eV above the ground state. These metastable configurations come into existence in synthesis at T ≥ 500 K, making experimentally realizable cluster compositions even more diverse.

Towardsoperandocomputational modeling in heterogeneous catalysis

“…Such parameterisation has been applied extensively by Johnston and coworkers, for bimetallic clusters such as Au–Pd 49 and Cu–Ag. 50 For ultrasmall vacuum-phase model catalytic particles, the small size both requires and allows for GO with more accurate, electronic structure methods. The most well studied class of systems is that of gold, and doped gold clusters, 51 – 54 for which the high degree of relativistic s–d hybridisation is key.…”

“…These studies are dominated by two classes of systems, the thiolate-protected gold 63 – 65 and silver 25 , 66 – 68 clusters and the hydrogen-passivated silicon clusters. 24 , 50 , 69 – 73 …”

“…New mutation operators combined with the previously re-parametrized 24 AM1 method improved convergence of GA, in particular for problematic cases with Si 14 H 20 and Si 6 H 6 stoichiometries. Recently, small H-passivated silicon clusters have also become the subject of a direct DFT EA-based GO investigation by Baturin et al 50 using a cluster EA implementation in the USPEX code. 83 This study of Si 10 H 2 m ( m = 0–12) nanoclusters highlighted how hydrogen concentration, temperature and density of low-energy isomers affect the structural and compositional flexibility of the nanocluster ensemble, possibly making experimentally realizable cluster compositions highly non-uniform, both structurally and compositionally.…”

Structure prediction and its applications in computational materials design

“…Baturin et al have applied this method to predict the atomic structure and stability of small silicon nanoclusters passivated by hydrogen. 64 Recently, the B 36 clusters which was synthesized and theoretically studied by Wang et al 65 Here we applied this method and reproduced the most two stable structures B 36 -C 6v and B 36 -D 4h within 10 generations (30 structures per generation). One can clearly see that B 36 clusters prefer to adopt high-symmetry structures.…”

Silicon buckyballs versus prismanes: Influence of spatial confinement on the structural properties and optical spectra of the Si18H12 and Si19H12 clusters

“…In Ref. [ ], stable geometries of Si 10 H 2 m nanoclusters ( m = 0–12) were found within the framework of the evolutional algorithm implemented in the USPEX program: their energies were calculated by means of the density functional theory. The results show that the arrangement of the silicon atoms in Si 10 H 16 cluster is close to the diamond crystal structure, while for the other structures the arrangement of Si atoms is unique.…”