Coherent effects and relaxation processes in liquid potassium

Новиков, А. Г.; Savostin, V. V.; Shimkevich, Alexander L.; Yulmetyev, Renat M.; Yulmetyev, Timur R.

doi:10.1016/s0921-4526(96)00469-3

Cited by 28 publications

(16 citation statements)

References 15 publications

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“…plane [6] portray the dynamics close to melting (T m 336:7 K) as markedly different from other alkali metals. Diffusive motions as seen in S q:el i Q; !…”

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confidence: 90%

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How Well Do We Know Atomic Motions of Simple Liquids?

et al. 2002

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Microscopic motions in molten potassium spanning three frequency decades are studied by neutronscattering techniques. These comprise well-defined density oscillations and stochastic particle rearrangements and both are modeled on microscopic grounds. While vibratory motions are shown to share characteristics with those of their parent crystals, dynamic correlations between a diffusing particle and its neighbors can be accounted for only semiquantitatively.

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“…plane [6] portray the dynamics close to melting (T m 336:7 K) as markedly different from other alkali metals. Diffusive motions as seen in S q:el i Q; !…”

mentioning

confidence: 90%

“…Diffusive motions as seen in S q:el i Q; ! , the incoherent part of the quasielastic spectra, are found to be ''solidlike'' [6], having large residence times for a particle within a ''cage.'' Naturally abundant K is a mostly coherent scatterer of neutrons (i.e., coherent to incoherent cross sections c = i 6:26).…”

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confidence: 99%

How Well Do We Know Atomic Motions of Simple Liquids?

et al. 2002

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“…For this reason, in the last thirty years, the microscopic dynamics of such systems has been widely investigated both experimentally, by means of Inelastic Neutron Scattering (INS), 1,2,3,4,5,6,7,8 and numerically 9,10,11,12,13,14,15,16 with the aim of clarifying in detail the mechanisms underlying the atomic motions at a microscopic level.…”

Section: Introductionmentioning

confidence: 99%

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

Monaco

Scopigno

Benassi

et al. 2004

The Journal of Chemical Physics

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The high frequency collective dynamics of molten potassium has been investigated by inelastic x-ray scattering, disclosing an energy/momentum transfer region unreachable by previous neutron scattering experiments (INS). We find that a two-step relaxation scenario, similar to that found in other liquid metals, applies to liquid potassium. In particular, we show how the sound velocity determined by INS experiments, exceeding the hydrodynamic value by ≈ 30%, is the higher limit of a speed up, located in the momentum region 1 < Q < 3 nm −1 , which marks the departure from the isothermal value. We point out how this phenomenology is the consequence of a microscopic relaxation process that, in turn, can be traced back to the presence of "instantaneous" disorder, rather than to the crossover from a liquid to solid-like response.

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“…From the experimental point of view, it is worth mentioning the pioneering inelastic neutron scattering (INS) experiment by Copley and Rowe [1] in liquid rubidium, while more recently many experimental efforts have been performed aiming to realize more and more accurate experiments: INS investigations have been devoted to liquid cesium [2], sodium [3], lithium [4], potassium [5] and again rubidium [6]. Simultaneously many theoretical and numerical studies have also been reported on the same systems [7][8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Evidence of short-time dynamical correlations in simple liquids

et al. 2002

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We report a molecular dynamics (MD) study of the collective dynamics of a simple monatomic liquid -interacting through a two body potential that mimics that of lithium-across the liquid-glass transition. In the glassy phase we find evidences of a fast relaxation process similar to that recently found in Lennard-Jones glasses. The origin of this process is ascribed to the topological disorder, i.e. to the dephasing of the different momentum Q Fourier components of the actual normal modes of vibration of the disordered structure. More important, we find that the fast relaxation persists in the liquid phase with almost no temperature dependence of its characteristic parameters (strength and relaxation time). We conclude, therefore, that in the liquid phase well above the melting point, at variance with the usual assumption of un-correlated binary collisions, the short time particles motion is strongly correlated and can be described via a normal mode expansion of the atomic dynamics.

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Coherent effects and relaxation processes in liquid potassium

Cited by 28 publications

References 15 publications

How Well Do We Know Atomic Motions of Simple Liquids?

How Well Do We Know Atomic Motions of Simple Liquids?

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

Evidence of short-time dynamical correlations in simple liquids

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