Damping Of Surface Plasmon Resonance Research Articles

Investigation of synthesized nanosized copper by polyol technique with graphite powder

Polyol method is a type of soft chemical method employed to prepare stable fine transition metals (TMs), without using any sophisticated instruments in a normal clean room environment. In the present work, pure nano-sized copper powder was prepared by reduction of copper (II) chloride dehydrate with sodium hydroxide in the glycerol environment at reaction temperature of 160°C for 17min. The Field Emission Scanning Electron Microscopy (FESEM) observation of synthesized copper powder showed the particle dimensions varying from 70 to 400nm. The Energy Dispersive Spectroscopy (EDS) and X-ray Diffraction (XRD) analysis supported the 98.46% purity of synthesized copper powder. The Rietveld analysis confirmed the cubic structure for synthesized copper with cell parameter: a=3.63Å. Whereas the Ultraviolet–Visible Spectroscopy (UV–Vis) revealed damping of surface plasmon resonance due to inactive chloride monolayer at the particle surface. This copper powder heat-treated in carbon environment showed the presence of copper oxalate phase using XRD analysis, noted from the peaks at 36.2° and 46.4° for (120) and (200) planes, respectively; and Fourier Transform Infra Red (FTIR) Spectroscopy backed the presence of copper oxide (Cu2O).

Radiative damping of surface plasmon resonance in spheroidal metallic nanoparticle embedded in a dielectric medium

The local field approach and kinetic equation method is applied to calculate the surface plasmon radiative damping in a spheroidal metal nanoparticle embedded in any dielectric media. The radiative damping of the surface plasmon resonance as a function of the particle radius, shape, dielectric constant of the surrounding medium and the light frequency is studied in detail. It is found that the radiative damping grows quadratically with the particle radius and oscillates with altering both the particle size and the dielectric constant of a surrounding medium. Much attention is paid to the electron surface-scattering contribution to the plasmon decay. All calculations of the radiative damping are illustrated by examples on the Au and Na nanoparticles.

Microscopic theory of surface-enhanced Raman scattering in noble-metal nanoparticles

We present a microscopic model for surface-enhanced Raman scattering (SERS) from molecules adsorbed on small noble-metal nanoparticles. In the absence of direct overlap of molecular orbitals and electronic states in the metal, the main enhancement source is the strong electric field of the surface plasmon resonance in a nanoparticle acting on a molecule near the surface. In small particles, the electromagnetic enhancement is strongly modified by quantum-size effects. We show that, in nanometer-sized particles, SERS magnitude is determined by a competition between several quantum-size effects such as the Landau damping of surface plasmon resonance and reduced screening near the nanoparticle surface. Using time-dependent local density approximation, we calculate spatial distribution of local fields near the surface and enhancement factor for different nanoparticles sizes.

Surface plasmon resonance of capped Au nanoparticles

In this Rapid Communication we show the relationship between surface plasmon resonance damping and the intensity of surface bonding for capped Au nanoparticles, (NPs). Up to now the influence of capping has been included as a phenomenological modification of the scattering constant. It is indicated here that the effective NP size is the parameter mainly affected by surface bonding. Experimental results in different Au-thiol NPs are shown to be in excellent agreement with the expression we propose for damping. Moreover, according to our model the resonance profile gives a deep insight of the interface bonding strength.