The Boson peak in alkali silicate glasses

McIntosh, C.M.; Toulouse, J.; Tick, Paul A.

doi:10.1016/s0022-3093(97)90133-2

Cited by 48 publications

(33 citation statements)

References 9 publications

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“…A pronounced peak can be observed at each density, even if its intensity decreases with density. At room pressure, the BP is found to be located at ω BP =1.3 THz, which is lower than the value found experimentally (Raman) of 1.95 THz (65 cm −1 ) 79 .…”

Section: Boson Peakcontrasting

confidence: 70%

Structural, vibrational, and thermal properties of densified silicates: Insights from molecular dynamics

Bauchy

2012

The Journal of Chemical Physics

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Structural, vibrational and thermal properties of densified sodium silicate (NS2) are investigated with classical molecular dynamics simulations of the glass and the liquid state. A systematic investigation of the glass structure with respect to density was performed. We observe a repolymerization of the network manifested by a transition from a tetrahedral to an octahedral silicon environment, the decrease of the amount of non-bridging oxygen atoms and the appearance of three-fold coordinated oxygen atoms (triclusters). Anomalous changes in the medium range order are observed, the first sharp diffraction peak showing a minimum of its full-width at half maximum according to density. The previously reported vibrational trends in densified glasses are observed, such as the shift of the Boson peak intensity to higher frequencies and the decrease of its intensity. Finally, we show that the thermal behavior of the liquid can be reproduced by the Birch-Murnaghan equation of states, thus allowing us to compute the isothermal compressibility.

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Section: Boson Peakcontrasting

confidence: 70%

Structural, vibrational, and thermal properties of densified silicates: Insights from molecular dynamics

Bauchy

2012

The Journal of Chemical Physics

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“…The former studies of alkali metaphosphates and alkali silicate glasses also showed that frequency of the Boson peak decreases with increasing mass of the alkali metal. 59,60 This dependence was approximately inversely proportional to the square root of the atomic mass for alkali silicate glasses or inversely proportional to the square of alkali metal-oxygen bond distances for alkali metaphosphates. 59,60 In our case this dependence is similar as that observed for the metaphosphates.…”

Section: -7mentioning

confidence: 99%

“…59,60 This dependence was approximately inversely proportional to the square root of the atomic mass for alkali silicate glasses or inversely proportional to the square of alkali metal-oxygen bond distances for alkali metaphosphates. 59,60 In our case this dependence is similar as that observed for the metaphosphates. The Љ͑ ͒ plots show also very clearly that the maximum of the Boson peak shifts to higher frequency and its bandwidth increases significantly when Rb + is replaced by K + .…”

Section: -7mentioning

confidence: 99%

Heat capacity, Raman, and Brillouin scattering studies of M2O–MgO–WO3–P2O5 glasses (M=K,Rb)

Mączka

Hanuza

Baran

et al. 2006

The Journal of Chemical Physics

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The authors report the results of temperature-dependent Brillouin scattering from both transverse and longitudinal acoustic waves, heat capacity studies as well as room temperature Raman scattering studies on M 2 O-MgO-WO 3 -P 2 O 5 glasses ͑M=K,Rb͒. These results were used to obtain information about structure and various properties of the studied glasses such as fragility, elastic moduli, ratio of photoelastic constants, and elastic anharmonicity. They have found that both glasses have similar properties but replacement of K + ions by Rb + ions in the glass network leads to decrease of elastic parameters and P 44 photoelastic constant due to increase of fragility. Based on Brillouin spectroscopy they show that a linear correlation between longitudinal and shear elastic moduli holds over a large temperature range. This result supports the literature data that the Cauchy-type relation represents a general rule for amorphous solids. An analysis of the Boson peak revealed that the form of the frequency distribution of the excess density of states is in agreement with the Euclidean random matrix theory. The reason of the observed shift of the maximum frequency of the Boson peak when K + ions are substituted for Rb + ions is also briefly discussed.

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“…This is an interesting point and may shed light on the enhancement of the heat conductance process mentioned in Physical Review Letters 103, 048301 (2009) [61] and PLOS ONE 8, e58770 (2013) [62]. As a function of temperature: at low temperatures the Boson peak corresponds to these local rearrangements with (mutual) reaction of one atom to another [63].…”

Section: Resultsmentioning

confidence: 74%

Effect of Size, Temperature, and Structure on the Vibrational Heat Capacity of Small Neutral Gold Clusters

Vishwanathan¹,

Springborg²

2017

J Material Sci Eng

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The vibrational heat capacity Cvib of a re-optimized neutral gold cluster was investigated at temperatures 0.5-300 K. The vibrational frequency of an optimized cluster was revealed by small atomic displacements using a numerical finite-differentiation method. This method was implemented using density-functional tight-binding (DFTB) approach. The desired set of system Eigen frequencies (3N -6) was obtained by diagonalization of the symmetric positive semi definite Hessian matrix. Our investigation revealed that the Cvib curve is strongly influenced by temperature, size, and structure and bond-order dependency. The effect of the range of interatomic forces is studied; especially the lower frequencies make a significant contribution to the heat capacity at low temperatures. In addition to that, we have exactly predicted the vibrational frequencies (ωi) which occur between 0.55 to 370.72 cm-1, depending on the nanoparticle morphology at T=0 for small neutral gold clusters AuN=3-20. This result has been proved and confirmed by the size effect values. It was found that beside the particle size, geometric shape, defect structure and an increase in asymmetry of nanoparticles effects on heat capacity. Surprisingly, the Boson peaks are typically ascribed to an excess density of vibrational states for the small clusters. Finally, temperature dependencies of the vibrational heat capacities of the re-optimized neutral gold clusters have been studied for the first time.

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The Boson peak in alkali silicate glasses

Cited by 48 publications

References 9 publications

Structural, vibrational, and thermal properties of densified silicates: Insights from molecular dynamics

Structural, vibrational, and thermal properties of densified silicates: Insights from molecular dynamics

Heat capacity, Raman, and Brillouin scattering studies of M2O–MgO–WO3–P2O5 glasses (M=K,Rb)

Effect of Size, Temperature, and Structure on the Vibrational Heat Capacity of Small Neutral Gold Clusters

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