Microscopic dynamics and relaxation processes in liquid hydrogen fluoride

Inelastic x-ray scattering and Brillouin light scattering measurements of the dynamic structure factor of liquid hydrogen fluoride have been performed in the temperature range T=214-283 K. The data, analyzed using a viscoelastic model with a two time-scale memory function, show a positive dispersion...

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Bibliographic Details
Published in:Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2004-12, Vol.70 (22), p.224302.1-224302.9, Article 224302
Main Authors: ANGELINI, R, GIURA, P, FIORETTO, D, MONACO, G, RUOCCO, G, SETTE, F
Format: Article
Language:English
Subjects:
ACTIVATION ENERGY
CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
Condensed matter: structure, mechanical and thermal properties
Exact sciences and technology
HYDROFLUORIC ACID
Lattice dynamics
LIGHT SCATTERING
LIQUIDS
Physics
RELAXATION
RELAXATION TIME
SOUND WAVES
SPECTRA
STRUCTURE FACTORS
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
Vibrational states in disordered systems
X-RAY DIFFRACTION
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Summary:Inelastic x-ray scattering and Brillouin light scattering measurements of the dynamic structure factor of liquid hydrogen fluoride have been performed in the temperature range T=214-283 K. The data, analyzed using a viscoelastic model with a two time-scale memory function, show a positive dispersion of the sound velocity c(Q) between the low frequency value c{sub 0}(Q) and the high frequency value c{sub {infinity}}{sub {alpha}}(Q). This finding confirms the existence of a structural ({alpha}) relaxation directly related to the dynamical organization of the hydrogen bonds network of the system. The activation energy E{sub a} of the process has been extracted by the analysis of the temperature behavior of the relaxation time {tau}{sub {alpha}}(T) that follows an Arrhenius law. The obtained value for E{sub a}, when compared with that observed in another hydrogen bond liquid as water, suggests that the main parameter governing the {alpha}-relaxation process is the number of hydrogen bonds per molecule.
ISSN:1098-0121
1550-235X
DOI:10.1103/PhysRevB.70.224302