Density functional theory calculations have been carried out to investigate the effect of the atomic under-coordination on
the bond contraction, lattice strain, and electron configuration of Cuboctahedral and Marks decahedral structures of
silver and copper nanoclusters. Our calculated results are consistent in trend with experimental measurements including
extended X-ray-absorption fine structure (EXAFS), scanning tunneling microscope/spectroscopy (STM/S), X-ray
photoelectron spectroscopy (XPS), and ultraviolet photoelectron spectra (UPS). This agreement approved the
prognostications made on the bond-order-length-strength (BOLS) correlation and nonbonding electron polarization
(NEP), suggesting that atomic under-coordination at the surface of nanoclusters cause bond contraction, which then leads
to lattice strain, charge densification, core electron entrapment, as well as polarization of valence charge. The results of
this work will contribute to the understanding of the intriguing properties of Ag and Cu nanoclusters.
Understanding the origin, the trend and the scale of the relative change of the mechanical strength and the dielectric properties of a nanometric solid is of great importance in designing solid-state device. Here we present a model that describes the nature and behavior of a nanosolid including spherical dots, wires and ultrathin films. Consistency between predictions and experimental observations confirms that the size-driven property-change originates from the chemical bond contraction at surface and the rise in the surface-to-volume ratio of the nanosolid. It is found that the bond contracts by as high as 14 percent and the corresponding Young's modulus increase by 100 percent at surface, and that the dielectric constant of semiconductors decreases with reducing the dimension of the solid, which leads to the blue shift in the photoluminescence and absorption edges.
Conference Committee Involvement (1)
International Symposium on Photonics and Applications