Gold: characteristics INDEX

The electronic absorption spectrum of metal nanocrystals in the visible region is dominated by the plasmon band. This absorption is due to the collective excitation of the itinerant electron gas on the particle surface and is characteristic of a nanocrystal of a given size. In metal colloids, surface plasmon excitations impart characteristic colors to the metal sols, the beautiful wine-red color of gold sols being well-known [6-8]. The dependence of the plasmon peak on the dielectric constant of the surrounding medium and the diameter of the nanocrystal was predicted theoretically by Mie and others at the turn of the last century [9-12]. The dependence of the absorption band of thiol-capped Au nanocrystals on solvent refractive index was recently verified by Templeton et al. [13]. Link et al. found that the absorption band splits into longitudinal and transverse bands in Au nanorods [6, 7]. 

A quantitative measurement of the depth of penetration of the diffracted electrons has been made previously (I) by depositing evaporated silver onto a gold crystal surface, using a calibrated silver source. Because the lattice structures are the same and the lattice constants differ by only 0.4%, the silver was found to deposit as a thin crystal on the gold surface. Owing to the different indexes of refraction and certain fine-structure characteristics... 

Polymer-embedded gold nanoparticles have been extensively studied [1]. Because of unique physical characteristics, gold-polymer nanocomposites are potentially useful for a number of advanced functional applications, especially in the optical and photonic fields. In particular, these materials can be used as light-stable color filters [2], polarizers [3, 4], ultra-low refractive index materials [5], nonlinear optical devices [6], optical sensors [7], and so on. However, still limited are the chemical routes that allow us to obtain monodispersed thiol-derivatized gold nanoparticles with controlled size to be embedded into poly-... 

In Exhibits 8.14 and 8.15, we use the same data to construct two efficient frontiers of portfolios—one without index-linked gilts as an available asset choice and one where index-linked can be selected. For the first frontier below, without linkers, gold is still selected for the lowest risk portfolios because of its diversifying characteristics, in spite of its dreadful risk-return trade-off over the 21 years. Flowever, it quickly disappears from optimal portfolios along the frontier if risk tolerance is raised a tiny bit. The asset mixes of a selection of portfolios along the frontier are also detailed. 

---