Effects of surface charge on the anomalous light extinction from metallic nanoparticles

•Monitoring of extraneous charges on metallic particles.•Far field scattering approach.•Anomalous scattering of inverted hierarchy in multipolar resonances.

The effects of extraneous surface charges on the anomalous extinction from metallic nanoparticles are studied via an application of the extended Mie theory by Bohren and Hunt. Due to the sensitivity of the higher multipolar resonance on the surface charges, it is found that quenching of the anomalous resonance can be observed with presence of only a modest amount of charges on these particles. The observed effects thus provide a rather sensitive mechanism for the monitoring of the neutrality of these nanoparticles using far field scattering approaches.