Plasmons in finite spherical ionic systems

TL;DR

This paper develops a theoretical model to study surface and volume plasmons in finite ionic systems, revealing size-dependent damping effects, resonance shifts, and potential for tunable plasmonic applications in electrolyte spheres.

Contribution

It introduces a new theoretical framework for ionic plasmons in finite systems, highlighting size effects, damping regimes, and resonance tuning possibilities distinct from metallic plasmons.

Findings

Size effect on damping is minimized at specific sphere sizes.

Resonance frequencies are red-shifted by several orders compared to metallic plasmons.

Ionic plasmon resonances can be tuned over a wide range depending on ion parameters.

Abstract

The challenging question on possible plasmon type excitations in finite ionic systems is discussed. The related theoretical model is formulated and developed in order to describe surface and volume plasmons of ion liquid in finite electrolyte systems. The irradiation of ionic surface plasmon fluctuations is studied in terms of the Lorentz friction of oscillating charges. The attenuation of surface plasmons in the ionic sphere is calculated and minimized with respect to the sphere size. Various regimes of approximation for description of size effect for damping of ionic plasmons are determined and a cross-over in damping size-dependence is demonstrated. The most convenient dimension of finite electrolyte system for energy and information transfer by usage of ionic dipole plasmons is determined. The overall shift of size effect to micrometer scale for ions in comparison to nanometer scale for electrons in metals is found and by several orders red shift of plasmonic resonances in ion systems is predicted in a wide range of variation depending of ion system parameters. This convenient opportunity of tuning of resonances differs ionic plasmons from plasmons in metals where electron concentration was firmly fixed.