Dynamics of weakly connected solids: Silica aerogels

Journal Article · Mon May 07 04:00:00 EDT 1990 · Physical Review Letters; (USA)

DOI:https://doi.org/10.1103/PhysRevLett.64.2316· OSTI ID:7056362

Schaefer, D W; Brinker, C J ^[1]; Richter, D; Farago, B; Frick, B ^[2]

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1. Sandia National Laboratories, Albuquerque, New Mexico 87185 (USA)
2. Institut Laue-Langevin, 38042 Grenoble (France)

Apply neutron spin-echo spectroscopy, we investigate low-energy vibrational excitations in a series of silica aerogels of varying connectivity. Connectivity is adjusted both by precursor solution chemistry and by heat treatment. Polymeric aerogels show fractonlike densities of states, whereas colloidal materials exhibit a peak in the {mu}ev regime. On sintering, the low-frequency excitations disappear. We conclude that neutron spin-echo spectroscopy provides a measure of the topological aspects of disordered materials.

• DOE Contract Number: AC04-76DP00789
• OSTI ID: 7056362
• Journal Information: Physical Review Letters; (USA), Journal Name: Physical Review Letters; (USA) Vol. 64:19; ISSN PRLTA; ISSN 0031-9007
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ADSORBENTS
AEROSOLS
BARYONS
CHEMISTRY
COLLOIDS
DATA
DISPERSIONS
ELEMENTARY PARTICLES
ENERGY-LEVEL DENSITY
EXPERIMENTAL DATA
FABRICATION
FERMIONS
HADRONS
HEAT TREATMENTS
INFORMATION
LATTICE VIBRATIONS
MATHEMATICS
MEDIUM TEMPERATURE
MIXTURES
NEUTRONS
NUCLEONS
NUMERICAL DATA
SCATTERING
SILICA GEL
SINTERING
SMALL ANGLE SCATTERING
SOLS
SOLUTIONS
SPIN ECHO
TOPOLOGY