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Demmel F. Non-Arrhenius behaviour of nickel self-diffusion in liquid Ni 77Si 23. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:395101. [PMID: 35858583 DOI: 10.1088/1361-648x/ac82d8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
Nickel self-diffusion was measured for a Ni77Si23alloy in the liquid state over a temperature range of about 400 K through quasielastic neutron scattering. At the two lowest temperature points the derived diffusion coefficients deviate from a high-temperature Arrhenius-type behaviour and indicate a change in dynamics above the liquidus temperature. A fit with a power-law temperature dependence as predicted by the mode coupling theory for the liquid to glass transition can describe the diffusion coefficients quite well over the whole measured temperature range. The obtained results agree with predictions from a classical molecular dynamics (MD)-simulation, which evidenced an increasing glass forming ability with increasing silicon content. A crossover to a super-Arrhenius behaviour was reported for metallic glass formers above the liquidus temperature and the here investigated NiSi alloy demonstrates the same signature.
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Affiliation(s)
- F Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, United Kingdom
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Demmel F. Sodium ion self-diffusion in molten NaBr probed over different length scales. Phys Rev E 2020; 101:062603. [PMID: 32688605 DOI: 10.1103/physreve.101.062603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/20/2020] [Indexed: 06/11/2023]
Abstract
The single-particle dynamics of sodium ions in molten sodium bromide has been investigated with quasielastic neutron scattering. A detailed and rather extensive data analysis procedure allowed determination of the pure sodium ion dynamics with increasing wave vector. Two different evaluation procedures agree perfectly on the resulting diffusion coefficient of sodium ions on long distances. A simple kinetic theory based on binary collisions of hard spheres is not able to reproduce the sodium diffusion coefficient. The derived reduced linewidth from modeling with a Lorentzian spectral function decreases with increasing wave vector towards the first structure factor maximum. That deviation from the hydrodynamic behavior signals the hindrance of the microscopic diffusion process due to the so-called cage effect when microscopic length scales are probed in a dense fluid. The observed quadratic wave-number-dependent decrease might be evidence for a coupling to density fluctuations as the source of the changes in the diffusion process. The results indicate that in the molten salt NaBr near the melting point the self-diffusion process might be governed by similar processes as already observed in dense metallic liquids.
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Affiliation(s)
- F Demmel
- ISIS Facility, Rutherford Appleton Laboratory, Didcot, OX11 0QX, United Kingdom
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Anento N, González LE, González DJ, Chushak Y, Baumketner A. Viscoelastic model for the dynamic structure factors of binary systems. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2004; 70:041201. [PMID: 15600399 DOI: 10.1103/physreve.70.041201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2004] [Indexed: 05/24/2023]
Abstract
This paper presents the viscoelastic model for the Ashcroft-Langreth dynamic structure factors of liquid binary mixtures. We also provide expressions for the Bhatia-Thornton dynamic structure factors and, within these expressions, show how the model reproduces both the dynamic and the self-dynamic structure factors corresponding to a one-component system in the appropriate limits (pseudobinary system or zero concentration of one component). In particular we analyze the behavior of the concentration-concentration dynamic structure factor and longitudinal current, and their corresponding counterparts in the one-component limit, namely, the self-dynamic structure factor and self-longitudinal current. The results for several lithium alloys with different ordering tendencies are compared with computer simulation data, leading to a good qualitative agreement, and showing the natural appearance in the model of the fast sound phenomenon.
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Affiliation(s)
- N Anento
- Departament de Física Fonamental, Universitat de Barcelona, 08028 Barcelona, Spain
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Celli M, Colognesi D, Zoppi M. Direct experimental access to microscopic dynamics in liquid hydrogen. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2002; 66:021202. [PMID: 12241159 DOI: 10.1103/physreve.66.021202] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2002] [Indexed: 05/23/2023]
Abstract
We have obtained the double-differential incoherent neutron scattering cross section of liquid and solid parahydrogen in various thermodynamic conditions using TOSCA, a time-of-flight, inverse geometry, crystal analyzer spectrometer, operating at the pulsed neutron source ISIS. The measured cross section provides direct experimental access to the self part of the center-of-mass inelastic structure factor of the parahydrogen molecules in the system. Data have been corrected for the experimental effects and then analyzed in the framework of the Young-Koppel model and the Gaussian approximation. The velocity autocorrelation functions and their energy spectra have been obtained from a fitting procedure, making use of the quantum generalized Langevin equation and of model memory functions, and finally compared to the most recent results of both molecular centroid dynamics and self-consistent quantum mode-coupling theory. Some dynamic quantities were also related to simple equilibrium properties and simulated through a standard path integral Monte Carlo code. Results are very interesting but still urge for further developments of theoretical and dynamic simulation approaches, as well as for more extensive experimental efforts.
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Affiliation(s)
- M Celli
- Consiglio Nazionale delle Ricerche, Istituto di Fisica Applicata Nello Carrara, Via Panciatichi 56/30, 50127 Firenze, Italy
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Reichman DR, Rabani E. A self-consistent mode-coupling theory for dynamical correlations in quantum liquids: Application to liquidpara-hydrogen. J Chem Phys 2002. [DOI: 10.1063/1.1458546] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Rabani E, Reichman DR. Molecular hydrodynamic approach to dynamical correlations in quantum liquids. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2002; 65:036111. [PMID: 11909169 DOI: 10.1103/physreve.65.036111] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2001] [Indexed: 05/23/2023]
Abstract
A quantum molecular hydrodynamic formalism is developed for the study of dynamics in quantum liquids. The method combines exact static input, generated by path-integral Monte Carlo, and an approximate form of the quantum memory function for the solution of the exact quantum generalized Langevin equation under consideration. This methodology is applied to the study of the spectrum of density fluctuations in liquid para-H2. Using a physically motivated approximation for the memory function, semiquantitative agreement is obtained for S(k,omega) in comparison to the recent experiments of Bermejo et al. [Phys. Rev. Lett. 84, 5359 (2000)]. Improvement of the methodology and future applications are discussed.
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Affiliation(s)
- Eran Rabani
- School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
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Giaquinta PV, Parrinello M, Tosi MP. Mass and charge transport in a simple molten salt. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3719/8/22/004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Dubey GS, Chaturvedi DK, Bansal R. Calculation of the longitudinal current spectra of liquid aluminium. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3719/12/11/010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Michler E, Hahn H, Schofield P. Calculation of the neutron scattering law of liquid aluminium. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0305-4608/7/5/019] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Canales M, Padró JA. Self-dynamic structure factor of dense liquids: theory and simulation. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2001; 63:011207. [PMID: 11304246 DOI: 10.1103/physreve.63.011207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2000] [Indexed: 05/23/2023]
Abstract
The self-intermediate dynamic structure factor Fs(k,t) of liquid lithium near the melting temperature is calculated by molecular dynamics. The results are compared with the predictions of several theoretical approaches, paying special attention to the Lovesey model and the Wahnström and Sjögren mode-coupling theory. To this end the results for the Fs(k,t) second memory function predicted by both models are compared with the ones calculated from the simulations.
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Affiliation(s)
- M Canales
- Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, B4-Campus Nord, 08034 Barcelona, Spain
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Dawidowski J, Chahid A, Bermejo FJ, Enciso E, Almarza NG. Dynamic correlations in a dense dipolar liquid. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1995; 52:2787-2796. [PMID: 9963725 DOI: 10.1103/physreve.52.2787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Torcini A, Balucani U, Verkerk P. Microscopic dynamics in liquid lithium. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1995; 51:3126-3138. [PMID: 9962991 DOI: 10.1103/physreve.51.3126] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Balucani U, Torcini A, Vallauri R. Liquid alkali metals at the melting point: Structural and dynamical properties. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:3011-3020. [PMID: 10006378 DOI: 10.1103/physrevb.47.3011] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Pastore G, Bernu B, Hansen JP, Hiwatari Y. Soft-sphere model for the glass transition in binary alloys. II. Relaxation of the incoherent density-density correlation functions. PHYSICAL REVIEW. A, GENERAL PHYSICS 1988; 38:454-462. [PMID: 9900183 DOI: 10.1103/physreva.38.454] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Sharma KC, Ranganathan S, Egelstaff PA, Soper AK. Dynamical properties of the Lorentz gas. PHYSICAL REVIEW. A, GENERAL PHYSICS 1987; 36:809-815. [PMID: 9898926 DOI: 10.1103/physreva.36.809] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Verkerk P, Suck J, Copley JR. Density fluctuations in liquid argon: Coherent dynamic structure factor along the 120-K isotherm obtained by neutron scattering. PHYSICAL REVIEW. A, GENERAL PHYSICS 1985; 31:3391-3414. [PMID: 9895894 DOI: 10.1103/physreva.31.3391] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Månsson T, Olsson LG, Larsson KE. The molecular motion in crystalline, plastic, and liquid neopentane studied by cold neutron scattering experiments. J Chem Phys 1977. [DOI: 10.1063/1.433859] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Olsson LG, Dahlborg U, Larsson KE. On the molecular motion in liquid neopentane. J Chem Phys 1976. [DOI: 10.1063/1.433087] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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