Inelastic neutron scattering due to acoustic vibrations confined in nanoparticles: theory and experiment

Lucien Saviot (1) , Caleb H. Netting (2) , Daniel B. Murray (2) , Stéphane Rols (3) , Alain Mermet (4) , Anne-Laure Papa (1) , Catherine Pighini (1) , Daniel Aymes (1) , Nadine Millot (1)

1 ICB - Laboratoire Interdisciplinaire Carnot de Bourgogne
2 MSP - Mathematics, Statistics and Physics Unit
3 ILL - Institut Laue-Langevin
4 LPCML - Laboratoire de Physico-Chimie des Matériaux Luminescents

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.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Lucien Saviot, Caleb H. Netting, Daniel B. Murray, Stéphane Rols, Alain Mermet, et al.. Inelastic neutron scattering due to acoustic vibrations confined in nanoparticles: theory and experiment. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2008, 78, pp.245426. ⟨10.1103/PhysRevB.78.245426⟩. ⟨hal-00394360⟩