Surface plasmon resonances in liquid metal nanoparticles

We have shown significant suppression of resonant properties of metallic nanoparticles at the surface plasmon frequency during the phase transition "solid-liquid" in the basic materials of nanoplasmonics (Ag, Au). Using experimental values of the optical constants of liquid and solid metals, we have calculated nanoparticle plasmonic absorption spectra. The effect was demonstrated for single particles, dimers and trimers, as well as for the large multiparticle colloidal aggregates. Experimental verification was performed for single Au nanoparticles heated to the melting temperature and above up to full suppression of the surface plasmon resonance. It is emphasized that this effect may underlie the nonlinear optical response of composite materials containing plasmonic nanoparticles and their aggregates.