Collective dynamics in molten potassium: An inelastic x-ray scattering study

Monaco, Andrea; Scopigno, T.; Benassi, P.; Giugni, Andrea; Monaco, G.; Nardone, M.; Ruocco, G.; Sampoli, M.

doi:10.1063/1.1689641

Cited by 25 publications

(24 citation statements)

References 33 publications

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“…Concerning the low q range, in the framework of generalized hydrodynamics, a quadratic behavior for ⌫͑q͒ would be expected instead and this was actually observed for example in potassium and lithium. 15,16 The linearity here reported is however in agreement with the report of Bodensteiner et al 10 In order to have a direct comparison with their data, we report in Fig. 6͑b͒ the width of the peaks of the longitudinal current together with the same quantity from Ref.…”

Section: Resultssupporting

confidence: 91%

“…This behavior is substantially different from the one of the other alkali metals, for which the microscopic process was found to be dominant and to be as well the main responsible for the positive dispersion of the sound velocity with respect to the adiabatic value. 15,16 In order to estimate the sound velocity dispersion we also reported in Fig. 4 the low frequency limit, v T = T / q as obtained from ͑i͒ the fit using Eq.…”

Section: Resultsmentioning

confidence: 99%

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High frequency dynamics in liquid Cs at high pressure

Giordano

Monaco

2009

The Journal of Chemical Physics

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We report on an inelastic x-ray scattering investigation of the high frequency dynamics of liquid cesium at 493 K and 1 GPa, which corresponds to a density 23% higher than that at the room pressure melting point. The analysis of the spectra, performed within the framework of the memory function approach suggests the existence of two different relaxation processes, i.e., the structural relaxation and a second faster one. The dynamical properties thus obtained are compared to those reported in the literature for room pressure conditions in order to investigate their dependence on pressure. The increase in density is found to largely affect the structural relaxation process, though leaving the acoustic damping almost unperturbed.

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Section: Resultssupporting

confidence: 91%

Section: Resultsmentioning

confidence: 99%

High frequency dynamics in liquid Cs at high pressure

Giordano

Monaco

2009

The Journal of Chemical Physics

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“…where is the convolution operator, A is a scaling factor, nx is the Bose factor, and x @!=k B T. In analogy to previous IXS studies on liquid metals [9][10][11][12], we chose a memory function composed of three exponential decays, each one accounting for a different relaxation process:…”

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confidence: 99%

High-Frequency Subsurface and Bulk Dynamics of Liquid Indium

Reichert¹,

Bencivenga

Wehinger³

et al. 2007

Phys. Rev. Lett.

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“…Such extension was also motivated by recent IXS studies on simple liquid metals near the melting temperature [12,13,14,15,16]. From a detailed line-shape analysis of S q (ω), the viscoelastic model was found to be unable to account for inelastic peaks in these systems.…”

Section: Introductionmentioning

confidence: 99%

Role of structural relaxations and vibrational excitations in the high-frequency dynamics of liquids and glasses

Chong

2006

Phys. Rev. E

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We present theoretical investigation on the high-frequency collective dynamics in liquids and glasses at microscopic length scales and terahertz frequency region based on the mode-coupling theory for ideal liquid-glass transition. We focus on recently investigated issues from inelastic-Xray-scattering and computer-simulation studies for dynamic structure factors and longitudinal and transversal current spectra: the anomalous dispersion of the high-frequency sound velocity and the nature of the low-frequency excitation called the boson peak. It will be discussed how the sound mode interferes with other low-lying modes present in the system. Thereby, we provide a systematic explanation of the anomalous sound-velocity dispersion in systems -ranging from high temperature liquid down to deep inside the glass state -in terms of the contributions from the structuralrelaxation processes and from vibrational excitations called the anomalous-oscillation peak (AOP). A possibility of observing negative dispersion -the decrease of the sound velocity upon increase of the wave number -is argued when the sound-velocity dispersion is dominated by the contribution from the vibrational dynamics. We also show that the low-frequency excitation, observable in both of the glass-state longitudinal and transversal current spectra at the same resonance frequency, is the manifestation of the AOP. As a consequence of the presence of the AOP in the transversal current spectra, it is predicted that the transversal sound velocity also exhibits the anomalous dispersion. These results of the theory are demonstrated for a model of the Lennard-Jones system.

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Collective dynamics in molten potassium: An inelastic x-ray scattering study

Cited by 25 publications

References 33 publications

High frequency dynamics in liquid Cs at high pressure

High frequency dynamics in liquid Cs at high pressure

High-Frequency Subsurface and Bulk Dynamics of Liquid Indium

Role of structural relaxations and vibrational excitations in the high-frequency dynamics of liquids and glasses

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