arXiv subjects

C. Noguez

Publications and source records attributed to C. Noguez.

4 recordsLinked to original sources

arXiv2006

Influence of Morphology on the Optical Properties of Metal Nanoparticles

The influence of morphology on the optical properties of silver nanoparticles is studied. A general relationship between the surface plasmon resonances and the morphology of each nanoparticle is established. The optical response is investigated for cubes and decahedrons with different truncations. We found that polyhedral nanoparticles composed with less faces show more surface plasmon resonances than spherical-like ones. It is also observed that the vertices of the nanoparticles play an important role in the optical response, because the sharpener they become, the greater the number of resonances. For all the nanoparticles, a main resonance with a dipolar character was identified as well as other secondary resonances of less intensity. It is also found that as the nanoparticle becomes more symmetric, the main resonance is always blue shifted.

physics.chem-ph↗

arXiv2005

The role of geometry on dispersive forces

The role of geometry on dispersive forces is investigated by calculating the energy between different spheroidal particles and planar surfaces, both with arbitrary dielectric properties. The energy is obtained in the non-retarded limit using a spectral representation formalism and calculating the interaction between the surface plasmons of the two macroscopic bodies. The energy is a power-law function of the separation of the bodies, where the exponent value depends on the geometrical parameters of the system, like the separation distance between bodies, and the aspect ratio among minor and major axes of the spheroid.

quant-ph↗

arXiv2005

Optical circular dichroism of single-wall carbon nanotubes

The circular dichroism (CD) spectra of single-wall carbon nanotubes are calculated using a dipole approximation. The calculated CD spectra show features that allow us to distinguish between nanotubes with different angles of chirality, and diameters. These results provide theoretical support for the quantification of chirality and its measurement, using the CD lineshapes of chiral nanotubes. It is expected that this information would be useful to motivate further experimental studies.

cond-mat.mtrl-sci↗

arXiv1995

First-Principles Studies of Hydrogenated Si(111)--7$\times$7

The relaxed geometries and electronic properties of the hydrogenated phases of the Si(111)-7$\times$7 surface are studied using first-principles molecular dynamics. A monohydride phase, with one H per dangling bond adsorbed on the bare surface is found to be energetically favorable. Another phase where 43 hydrogens saturate the dangling bonds created by the removal of the adatoms from the clean surface is found to be nearly equivalent energetically. Experimental STM and differential reflectance characteristics of the hydrogenated surfaces agree well with the calculated features.

cond-mat↗