Why the aspect ratio? Shape equivalence for the extinction spectra of gold nanoparticles

TL;DR

This paper proposes using mass distribution moments instead of aspect ratio to compare extinction spectra of gold nanoparticles, leading to better shape equivalence and spectral correspondence.

Contribution

It introduces a new criterion based on mass distribution moments for comparing nanoparticle spectra, improving upon the traditional aspect ratio approach.

Findings

Mass distribution moments provide a better spectral match than aspect ratio.

Shape equivalence is more accurately achieved through moments of mass distribution.

The method applies to various shapes and sizes of gold nanoparticles.

Abstract

We compare the light extinction spectra of elongated gold nanoparticles with different shapes (cylinder, spherocylinder and ellipsoid) and sizes of 10 to 100~nm. We argue that the equivalence of the various moments of mass distribution is the natural comparison criterion -rather than the length-to-diameter (aspect) ratio generally used in the literature- and that it leads to better spectral correspondence between the various shapes.