Vibrations of nanoparticles: From nanospheres to fcc cuboctahedra

Abstract

Vibrational modes of gold nanoparticles grown in a silicate glass were studied through high-resolution low-frequency Raman scattering. The spectra evidence a clear splitting of the quadrupolar mode into two components, unseen in lower-resolution Raman experiments. This splitting turns out to be quantitatively consistent with the lifting of degeneracy expected as the nanoparticles evolve from nanospheres to faceted crystalline nanocrystals.