Atomistic structure and collective dynamics in liquid Pb along the melting line up to 70 GPa: A first-principles molecular dynamics study

Bryk, Taras; Demchuk, Taras; Jakse, N.

doi:10.1103/physrevb.99.014201

Cited by 20 publications

(30 citation statements)

References 59 publications

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“…where The high quality of the IXS data acquired permits to assign a value to L and L even at small values of q, in the interval 1-2 nm −1 . In the high-q region (q > 5 nm −1 ) an additional feature in the inelastic wings of the IXS spectrum is observed, in agreement with experimental observation in several other classes of glass [46][47][48][49][50][51][52][53][54][55][56][57][58]. Similar features are commonly related to "projection" of transverse into longitudinal dynamics.…”

Section: B Inelastic Neutron Scattering Experimentssupporting

confidence: 88%

“…The exploiting of the GBA in this framework can be relevant because features in the dynamic structure factor possibly related to the mixing of polarizations have been observed experimentally [50,54,109,110] and by MD simulations [55,56,58] in several liquids. Similar developments could also support the understanding of the origin of the two-peak structure observed in the transverse current spectra of liquids in the high-frequency region, as attested by recent MD studies [57,111,112].…”

Section: Discussionsupporting

confidence: 67%

“…The mixing of polarizations in a local elastically heterogeneous medium is qualitatively predicted by the elementary elasticity theory, which states that a purely polarized wave impinging on an interface between two different elastic media shall be transformed in waves with mixed polarization [45]. Features in S(q, E ) possibly attributable to acoustic excitations with mixed polarization have been observed by IXS or INS experiments [46][47][48][49][50][51][52][53][54], as well as by MD simulations [55][56][57][58] in several topologically disordered systems in the first pseudo-Brillouin zone, with a q onset typically ∼5 nm −1 . Despite this, one meets the lacking of analytical models addressing the occurrence of disorder-induced mixing of polarizations, which has, furthermore, never been related to the Rayleigh scattering in the RMT framework.…”

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confidence: 99%

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Rayleigh scattering and disorder-induced mixing of polarizations in amorphous solids at the nanoscale: 1-octyl-3-methylimidazolium chloride glass

et al. 2020

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Acousticlike excitations in topologically disordered media at mesocale/nanoscale present anomalous features with respect to the Debye's theory. The so-called Rayleigh scattering manifests in a strong increase of the attenuation of the acousticlike excitations and a softening of the phase velocity with respect to its continuum limit value. Mean field models developed in the random media theory framework can successfully predict the occurrence, at the proper length scale, of Rayleigh scattering. The overall attenuation in the Rayleigh region is, however, underestimated. In the framework of random media theory we developed an analytical model, which permits a quantitative description of the acousticlike excitations in topological glasses in the whole first pseudo-Brillouin zone. The underestimation of the Rayleigh scattering is avoided and, importantly, the model allows to account also for the polarization properties of the acousticlike excitations. In a three-dimensional medium an acoustic wave is characterized by its phase velocity, intensity, and polarization. Rayleigh scattering emphasizes how the topological disorder affects the first two properties. The topological disorder is, however, expected to influence also the third one. In common with the Rayleigh scattering, hallmarks possibly related to the mixing of polarizations have been traced in different classes of amorphous solids at nanoscale. The quantitative theoretical approach developed permits to demonstrate how the mixing of polarizations generates a distinctive feature in the dynamic structure factor of amorphous solids. The modeling capability of the proposed mean field theory is tested on glassy 1-octyl-3-methylimidazolium chloride, whose spatial distribution of the elastic moduli is well assessed and can be experimentally characterized. Contrast between theoretical and experimental features for the selected glass reveals an excellent agreement. The mean field approach we present retains a certain degree of generality and can be possibly extended to different stochastic media or different wave fields.

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Section: B Inelastic Neutron Scattering Experimentssupporting

confidence: 88%

Section: Discussionsupporting

confidence: 67%

mentioning

confidence: 99%

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Rayleigh scattering and disorder-induced mixing of polarizations in amorphous solids at the nanoscale: 1-octyl-3-methylimidazolium chloride glass

et al. 2020

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“…For both metals, we have found two branches with the high-frequency branch existing over a limited q-range around the position of the main peak of the S(q). To our knowledge, the emergence of a second, high-frequency, transverse branch has been found in high pressure l-Li, l-Na, l-Fe, l-Pb and l-Al [31,32,33,34], but recently some AIMD studies at ambient pressure have also unveiled a second high-frequency transverse branch, in particular for l-Ni, l-Tl, l-Zn and l-Sn near melting [7,35,36,37]. In all cases, this new branch appears for q-values greater than the first pseudo-Brillouin zone boundary, i.e.…”

Section: Collective Dynamicsmentioning

confidence: 80%

Properties of bulk liquid Pd and Pt and their free liquid surface studied with first principles techniques

Río¹,

González²,

González³

2020

Modelling Simul. Mater. Sci. Eng.

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We have performed first principles computer simulations in order to study the structural and dynamic properties of bulk liquid Pd and Pt near their melting points. We find good agreement with the available experimental static structure and transport properties, and furthermore we provide more detailed information that is not available from experiments. Additional simulations have also been undertaken so as to study the free liquid surface of both liquid metals. The calculated longitudinal ionic density profile exhibits an oscillatory behavior whose properties have been analyzed. For both metals, the associated intrinsic surface structure factor presents a marked maximum related to surface layering.

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“…Here our concern is to present experimental results for S(Q, ω), and to evaluate the ability of AIMD calculations to properly describe also the dynamics of liquid Ag, as already satisfactorily verified for Au and other liquid metals at ambient pressure, such as Ti [34], Fe [35], Ni, [36], or Zn [37], to mention only some recent studies. Recent AIMD studies have also addressed the case of liquid metals at high pressures, where new dynamic features may appear [38][39][40], but for which experimental data are mostly still missing.…”

Section: Introductionmentioning

confidence: 99%

Neutron Brillouin scattering and ab initio simulation study of the collective dynamics of liquid silver

et al. 2020

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We present a thorough investigation of the collective dynamics of liquid Ag combining neutron Brillouin scattering and ab initio molecular dynamics (AIMD) determinations of the dynamic structure factor S(Q, ω). The main scope of this work is not only to provide experimental results for some important dynamical properties of this liquid metal in the wave-vector range 4 < Q < 16 nm −1 , but also to inquire about the scarce detectability of shear waves apparently characterizing two elements of group IB, differently from other metals. In fact, as in the case of Au, a transverse-like dynamics is not deducible from the experimental S(Q, ω) of Ag, despite the indisputable quality of the neutron data collected on the BRISP spectrometer at the Institut Laue Langevin in Grenoble. However, the significant agreement between experiment and AIMD calculations allowed for an indepth study of the simulated S(Q, ω) in a Q range overlapping and extending the experimental one. A multimode analysis, already proven very successful in the description of various dynamical properties of fluid systems, is shown to be extremely effective also to analyze the intermediate scattering function predicted by AIMD at the various Q values, and eventually enables a reliable determination of both longitudinal and transverse branches in the dispersion curve of this liquid. Throughout the paper we highlight the importance of referring to theoretically well-founded models for S(Q, ω) and of imposing physical constraints in a fit-based analysis: These ensure that the used models obey fundamental properties of the dynamic structure factor.

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Atomistic structure and collective dynamics in liquid Pb along the melting line up to 70 GPa: A first-principles molecular dynamics study

Cited by 20 publications

References 59 publications

Rayleigh scattering and disorder-induced mixing of polarizations in amorphous solids at the nanoscale: 1-octyl-3-methylimidazolium chloride glass

Rayleigh scattering and disorder-induced mixing of polarizations in amorphous solids at the nanoscale: 1-octyl-3-methylimidazolium chloride glass

Properties of bulk liquid Pd and Pt and their free liquid surface studied with first principles techniques

Neutron Brillouin scattering and ab initio simulation study of the collective dynamics of liquid silver

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