Inelastic neutron scattering due to acoustic vibrations confined in   nanoparticles: theory and experiment
  The inelastic scattering of neutrons by nanoparticles due to acoustic vibrational modes (energy below 10 meV) confined in nanoparticles is calculated using the Zemach-Glauber formalism. Such vibrational modes are commonly observed by light scattering techniques (Brillouin or low-frequency Raman scattering). We also report high resolution inelastic neutron scattering measurements for anatase TiO2 nanoparticles in a loose powder. Factors enabling the observation of such vibrations are discussed. These include a narrow nanoparticle size distribution which minimizes inhomogeneous broadening of the spectrum and the presence of hydrogen atoms oscillating with the nanoparticle surfaces which enhances the number of scattered neutrons. 
Lucien Saviot, Caleb H. Netting, Daniel B. Murray, St\'ephane Rols,   Alain Mermet, Anne-Laure Papa, Catherine Pighini, Dani...