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Journal of Physical Studies 20(1/2), Article 1701 [9 pages] (2016)
DOI: https://doi.org/10.30970/jps.20.1701 BROADENING OF SURFACE PLASMON RESONANCE LINE IN SPHEROIDAL METALLIC NANOPARTICLESN. I. Grigorchuk
Bogolyubov Institute for Theoretical Physics, NAS of Ukraine, |
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The local field approach and kinetic equation method is applied to calculate the line broadening of the surface plasmon resonance (SPR) in a spheroidal metal nanoparticle (MN) embedded in any dielectric media. Usually, both the surface and the radiative damping mechanisms play an important role in the plasmon decay. In the MNs of a smaller radii, the penetration depth of the plasmon field reduces and becomes more localized near the surface. As a result, the bulk-induced loss processes play only a minor role and the electronic excitations generated by the surface potential dominate.
The radiative damping of the SPR is an important parameter since it would help to analyze the specificity of the transformation of the collective electron oscillation energy into the optical far field. In the former similar works, it was dropped from the account the fact that the role of an external electric field can play the inner electric field in MN. The purpose of this paper is to calculate the radiative damping of the SPR under the effect of inner electric field, for the case when the mean free path of the electrons is larger than the particle size and their scattering on the particle surface plays an important role.
In presented work the radiative damping of the SPR 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.
PACS number(s): 78.67.Bf, 73.20.Mf, 46.40.Ff