The smallest free-electron sphere sustaining multipolar surface plasmon oscillation

TL;DR

This paper investigates the oscillation frequencies and decay rates of surface plasmon modes in simple-metal spheres across various sizes, challenging traditional assumptions in the low radius limit using classical electrodynamics.

Contribution

It provides a detailed analysis of multipolar surface plasmon oscillations without size assumptions, refining understanding of plasmon behavior in small metallic spheres.

Findings

Identifies the smallest sphere size supporting multipolar surface plasmon oscillations.

Re-examines classical expectations for plasmon frequencies in small spheres.

Provides a comprehensive model for plasmon decay rates as a function of sphere size.

Abstract

We study the oscillation frequencies and radiative decay rates of surface plasmon modes of a simple-metal sphere as a function of sphere radius without any assumptions concerning the sphere size. We re-examine within the framework of classical electrodynamics the usual expectations for multipolar plasmon frequency in the so called "low radius limit" of the classical picture.