Sound Attenuation at Terahertz Frequencies and the Boson Peak of Vitreous Silica

Baldi, G.; Giordano, Valentina M.; Monaco, G.; Ruta, Beatrice

doi:10.1103/physrevlett.104.195501

Cited by 157 publications

(216 citation statements)

References 34 publications

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“…In the low-wave-vector range the sound velocity, at both temperatures, is affected by a negative dispersion effect, followed by a positive dispersion at higher Q's. The negative dispersion has been discussed previously 23 and it has been observed also in other systems. 22,25 The data at room temperature indicate that v L increases markedly with increasing temperature.…”

Section: A Dispersion and Dampingsupporting

confidence: 67%

“…23 The variation of the sound velocity with temperature is found to be comparable to that determined by means of Brillouin light scattering (BLS). 36 Using the resulting Debye frequency we show that the temperature dependence of the BP in silica does not follow the elastic medium transformation, confirming the observation of Ref.…”

Section: Introductionsupporting

confidence: 57%

“…The apparent sound velocity shows a negative dispersion and the sound attenuation undergoes a transition from a lowfrequency region where it is proportional to the fourth power of the frequency to a quadratic frequency dependence at high frequencies. This behavior has been observed in three systems with different degree of fragility: the glass of glycerol, 22 silica glass 23,24 at elevated temperatures, and sorbitol glass. 25 These experimental results have been confirmed by molecular dynamics simulations of a Lennard-Jones glass performed on an exceptionally large simulation box, containing 10 7 particles.…”

Section: Introductionmentioning

confidence: 83%

“…[27][28][29][30] On the contrary, the damping undergoes a transition from ∝ Q 4 in the low-Q range to ∝ Q 2 at high Q's (see Ref. 23 for a thorough discussion on this point). This behavior, best visible in the high-temperature data, is detectable also at room temperature.…”

Section: A Dispersion and Dampingmentioning

confidence: 99%

“…By means of IXS it has been recently observed [22][23][24][25] that the BP is associated with anomalies in the elastic properties of the glass. The apparent sound velocity shows a negative dispersion and the sound attenuation undergoes a transition from a lowfrequency region where it is proportional to the fourth power of the frequency to a quadratic frequency dependence at high frequencies.…”

Section: Introductionmentioning

confidence: 99%

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Elastic anomalies at terahertz frequencies and excess density of vibrational states in silica glass

2011

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We study the temperature dependence of acousticlike excitations measured by means of inelastic x-ray scattering at terahertz frequencies in silica glass. The apparent sound velocity shows, between 300 and 1600 K, the same temperature variation measured, at lower frequencies, by Brillouin light scattering. On the contrary the vibrations at the boson peak (BP) present a much stronger temperature dependence, as indicated by neutron scattering data. The measured dispersion and damping are used to compute the contribution to the vibrational density of states (VDOS) coming from the propagating acousticlike modes. This part of the VDOS accounts only for a fraction of the BP intensity, indicating that other kinds of excitation accumulate in this frequency range. It is consequently not surprising that the BP does not follow the temperature evolution of the Debye frequency, which describes the modification of the continuum medium. Finally we present a comparison between the experimentally accessible quantities and a recently proposed model for the vibrations in glasses, based on the assumption of random spatial variations of the shear modulus [Schirmacher, Europhys. Lett. 73, 892 (2006)].

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Section: A Dispersion and Dampingsupporting

confidence: 67%

Section: Introductionsupporting

confidence: 57%

Section: Introductionmentioning

confidence: 83%

Section: A Dispersion and Dampingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Elastic anomalies at terahertz frequencies and excess density of vibrational states in silica glass

2011

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Local Deformation of Glasses is Mediated by Rigidity Fluctuation on Nanometer Scale

et al. 2018

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Microscopic deformation processes determine defect formation on glass surfaces and, thus, the material's resistance to mechanical failure. While the macroscopic strength of most glasses is not directly dependent on material composition, local deformation and flaw initiation are strongly affected by chemistry and atomic arrangement. Aside from empirical insight, however, the structural origin of the fundamental deformation modes remains largely unknown. Experimental methods that probe parameters on short or intermediate length‐scale such as atom–atom or superstructural correlations are typically applied in the absence of alternatives. Drawing on recent experimental advances, spatially resolved Raman spectroscopy is now used in the THz‐gap for mapping local changes in the low‐frequency vibrational density of states. From direct observation of deformation‐induced variations on the characteristic length‐scale of molecular heterogeneity, it is revealed that rigidity fluctuation mediates the deformation process of inorganic glasses. Molecular field approximations, which are based solely on the observation of short‐range (interatomic) interactions, fail in the prediction of mechanical behavior. Instead, glasses appear to respond to local mechanical contact in a way that is similar to that of granular media with high intergranular cohesion.

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Azahelicene Superbases as MAILD Matrices for Acidic Analytes

et al. 2013

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Fitting the profile: A superbasic 1,14‐diaza[5]helicene can serve as an efficient, ionless matrix for matrix‐assisted ionization/laser desorption (MAILD) spectrometry. The matrix outperforms other bases by acting as a kinetically active proton sponge and is highly suitable for high‐throughput metabolomics analysis. There is a correlation between the basicity (and proton‐sponge character) of matrices and their efficacy in MAILD‐MS.

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Sound Attenuation at Terahertz Frequencies and the Boson Peak of Vitreous Silica

Cited by 157 publications

References 34 publications

Elastic anomalies at terahertz frequencies and excess density of vibrational states in silica glass

Elastic anomalies at terahertz frequencies and excess density of vibrational states in silica glass

Local Deformation of Glasses is Mediated by Rigidity Fluctuation on Nanometer Scale

Azahelicene Superbases as MAILD Matrices for Acidic Analytes

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