Polarization properties of low frequency inelastic scattering by acoustic phonons in gold nanoclusters

Abstract

Polarized low frequency Raman spectra (LOFIS) of gold nanoparticles supported on CeO₂ and Fe₂O₃ catalytic matrices have been studied for two differently prepared metal oxide-gold samples. Depolarization ratios, ρ_S, were measured after an accurate elastic peak subtraction and a deconvolution, with a two-bands fitting function, of the whole low frequency Raman spectra of these materials. From the values of ρ_S measured through the ratios of the integrated areas, it seems possible to conclude that the total LOFIS envelopes are constituted by l = 2 and l = 0 surface spheroidal modes of quadrupolar and radial types respectively.