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Titolo:
Inelastic neutron scattering on silica xerogel porous systems
Autore:
Fontana, A; Montagna, M; Righetti, L; Rossi, F; Cicognani, G; Dianoux, AJ; Terki, F;
Indirizzi:
Univ Trent, Dipartimento Fis, I-38050 Povo, Trento, Italy Univ Trent PovoTrento Italy I-38050 nto Fis, I-38050 Povo, Trento, Italy Univ Trent, INFM, I-38050 Povo, Trento, Italy Univ Trent Povo Trento Italy I-38050 t, INFM, I-38050 Povo, Trento, Italy Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France Inst Max Von Laue Paul Langevin Grenoble France F-38042 Grenoble, France Univ Montpellier 2, Lab Verres, UMR 5587, F-34095 Montpellier, France UnivMontpellier 2 Montpellier France F-34095 -34095 Montpellier, France
Titolo Testata:
JOURNAL OF NON-CRYSTALLINE SOLIDS
fascicolo: 1-3, volume: 280, anno: 2001,
pagine: 217 - 221
SICI:
0022-3093(200102)280:1-3<217:INSOSX>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
LOW-FREQUENCY MODES; VITREOUS SILICA; GLASSES; RAMAN; EXCITATIONS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
18
Recensione:
Indirizzi per estratti:
Indirizzo: Fontana, A Univ Trent, Dipartimento Fis, I-38050 Povo, Trento, Italy Univ Trent Povo Trento Italy I-38050 38050 Povo, Trento, Italy
Citazione:
A. Fontana et al., "Inelastic neutron scattering on silica xerogel porous systems", J NON-CRYST, 280(1-3), 2001, pp. 217-221

Abstract

New coherent inelastic neutron scattering measurements on silica xerogels in the 300-1000 K temperature range are presented and compared with those obtained in vitreous silica (heralux). The spectra show the presence of the Boson peak, at temperatures, where the quasi-elastic contribution due to absorbed water is negligible. The Boson peak in silica xerogels is at a frequency of around 5 meV (40 cm(-1)) and has a shape similar to that of melted silica, even in the smaller density xerogels. This important result seems to indicate that the disorder introduced by the presence of pores does not affect the density of states in frequency region. This evidence is also confirmed by changes in the inelastic structure factor S(Q,omega), measured at the frequencies of the Boson peak as a function of the exchanged Q. (C) 2001 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/09/20 alle ore 05:48:12