title: Vibrational and electronic excitations in gold nanocrystals.
abstract: An experimental analysis of all elementary excitations--phonons and electron-holes--in gold nanocrystals has been performed using plasmon resonance Raman scattering. Assemblies of monodisperse, single-crystalline gold nanoparticles, specific substrates and specific experimental configurations have been used. Three types of excitations are successively analyzed: collective quasi-acoustical vibrations of the particles (Lamb's modes), electron-hole excitations (creating the so-called "background" in surface-enhanced Raman scattering) and ensembles of atomic vibrations ("bulk" phonons). The experimental vibrational density of states extracted from the latter contribution is successfully compared with theoretical estimations performed using atomic simulations. The dominant role of surface atoms over the core ones on lattice dynamics is clearly demonstrated. Consequences on the thermodynamic properties of nanocrystals such as the decrease of the characteristic Debye temperature are also considered.
authors: Université de Toulouse, CEMES CNRS, 29 rue Jeanne Marvig, BP 94347, 31055 Toulouse Cedex 4, France. carles@cemes.fr.
authors: Maxime
authors: M
authors: Bayle
authors: Nicolas
authors: N
authors: Combe
authors: Neralagatta M
authors: NM
authors: Sangeetha
authors: Guillaume
authors: G
authors: Viau
authors: Robert
authors: R
authors: Carles