Stimulated boson-peak light scattering in an aqueous suspension of spherical nanoparticles of amorphous SiO2 of similar sizes.

A forward-directed high-efficiency stimulated inelastic light scattering was detected in an aqueous suspension of spherical nanoparticles (nanoballs) of amorphous SiO2 of similar sizes (0.25 µm) with a concentration of 1013 cm-3. In the stimulated scattering spectrum, there was an intense forward directed Stokes component with a frequency shift of 0.54 cm-1, corresponding to the boson peak mode of spherical nanoparticles. The results obtained are of interest for non-equilibrium excitation of spherical particles of similar sizes of different nature present in liquids (clusters, fullerenes, spherical macromolecules, viruses, etc.).