Surface scattering contribution to the plasmon width in embedded Ag nanospheres.

Area of Science:

• Physics
• Materials Science
• Nanotechnology

Background:

• Classical Mie theory does not fully explain the broadening of localized surface plasmon resonance (LSPR) in nanometer-sized metal particles.
• Deviations from classical predictions are observed, particularly in smaller nanoparticles.

Purpose of the Study:

• To develop and apply a model that quantitatively relates LSPR width to nanoparticle radius and surrounding medium permittivity.
• To investigate the influence of non-local surface screening and size quantization on LSPR broadening.
• To compare model predictions with experimental data for silver nanospheres.

Main Methods:

• Utilizing a theoretical model incorporating non-local surface screening and size quantization effects.
• Analyzing the dependence of LSPR width on nanoparticle radius (R) and the permittivity of the surrounding medium (ε(m)).
• Comparing calculated LSPR widths with experimental measurements for silver (Ag) nanospheres.

Main Results:

• For Ag nanospheres > 8 nm, surface non-local dynamical effects are dominant over bulk scattering up to 25 nm.
• LSPR width shows an inverse relationship with particle size.
• LSPR width exhibits a non-monotonic dependence on ε(m), with a maximum for Ag at ε(m) ≈ 2.5.

Conclusions:

• The developed model successfully explains the observed LSPR broadening in nanometals.
• Non-local surface effects are crucial for understanding plasmon behavior in small metal nanoparticles.
• The findings provide a quantitative link between LSPR properties, nanoparticle size, and the dielectric environment.