Surface scattering contribution to the plasmon width in embedded Ag nanospheres

TL;DR

This paper models how surface scattering affects the plasmon resonance width in silver nanospheres, showing that surface effects dominate over bulk scattering for particles larger than 8 nm and depend on particle size and surrounding medium.

Contribution

It introduces a quantitative model linking plasmon width to nanoparticle size and medium permittivity, emphasizing surface scattering effects in silver nanospheres.

Findings

Surface scattering dominates for particles >8 nm

LSPR width inversely proportional to particle size

Maximum width at medium permittivity ~2.5

Abstract

Nanometer-sized metal particles exhibit broadening of the localized surface plasmon resonance (LSPR) in comparison to its value predicted by the classical Mie theory. Using our model for the LSPR dependence on non-local surface screening and size quantization, we quantitatively relate the observed plasmon width to the nanoparticle radius $R$ and the permittivity of the surrounding medium $\epsilon_m$. For Ag nanospheres larger than 8 nm only the non-local dynamical effects occurring at the surface are important and, up to a diameter of 25 nm, dominate over the bulk scattering mechanism. Qualitatively, the LSPR width is inversely proportional to the particle size and has a nonmonotonic dependence on the permittivity of the host medium, exhibiting for Ag a maximum at $\epsilon_m\approx2.5$. Our calculated LSPR width is compared with recent experimental data.