Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Low-energy vibrational dynamics of hydrogenated silica gels
Autore:
Bartolotta, A; Carini, G; DAngelo, G; Fontana, A; Rossi, F; Tripodo, G;
Indirizzi:
Univ Messina, Dipartimento Fis, I-98166 S Agata, ME, Italy Univ Messina SAgata ME Italy I-98166 nto Fis, I-98166 S Agata, ME, Italy Univ Messina, Ist Nazl Fis Mat, I-98166 S Agata, ME, Italy Univ Messina SAgata ME Italy I-98166 Fis Mat, I-98166 S Agata, ME, Italy Univ Trent, Dipartimento Fis, I-38050 Trent, Italy Univ Trent Trent Italy I-38050 t, Dipartimento Fis, I-38050 Trent, Italy Univ Trent, Ist Nazl Fis Mat, I-38050 Trent, Italy Univ Trent Trent Italy I-38050 t, Ist Nazl Fis Mat, I-38050 Trent, Italy
Titolo Testata:
JOURNAL OF NON-CRYSTALLINE SOLIDS
, volume: 245, anno: 1999,
pagine: 9 - 14
SICI:
0022-3093(19990401)245:<9:LVDOHS>2.0.ZU;2-A
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHOSPHATE-GLASSES; SCATTERING; EXCESS; RAMAN; HEAT;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
13
Recensione:
Indirizzi per estratti:
Indirizzo: Carini, G Univ Messina, Dipartimento Fis, I-98166 S Agata, ME, Italy Univ Messina S Agata ME Italy I-98166 -98166 S Agata, ME, Italy
Citazione:
A. Bartolotta et al., "Low-energy vibrational dynamics of hydrogenated silica gels", J NON-CRYST, 245, 1999, pp. 9-14

Abstract

A comparative study of low temperature specific heat (1.5-25 K) and low frequency Raman scattering (<150 cm(-1)) in sol-gel hydrogenated silica samples has been carried out to analyse the variations of the dynamical properties of a disordered system as a function of the changes of the network connectivity. Variations of the connectivity in the range from 3 to 3.75, obtained by decreasing the hydrogen content or by increasing the density of the as-prepared samples (achieved by thermal treatments at various temperatures)alter the magnitude of the quasi-elastic scattering, as well as the density of low energy vibrations determining the low temperature specific heat. Using as a reference observations in quenched vitreous silica, which has thelargest connectivity, it is shown that decreasing connectivity leads to (i) a softening of the network and (ii) a smaller excess of additional lower energy vibrations over the predictions of the Debye theory. (C) 1999 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 02/12/20 alle ore 18:34:24