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Pan H, Kalman GJ, Hartmann P, Donkó Z. Strongly coupled Yukawa trilayer liquid: Structure and dynamics. Phys Rev E 2020; 102:043206. [PMID: 33212692 DOI: 10.1103/physreve.102.043206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 09/09/2020] [Indexed: 11/07/2022]
Abstract
The equilibrium structure and the dispersion relations of collective excitations in trilayer Yukawa systems in the strongly coupled liquid regime are examined. The equilibrium correlations reveal a variety of structures in the liquid phase, reminiscent of the corresponding structures in the solid phase. At small layer separation substitutional disorder becomes the governing feature. Theoretical dispersion relations are obtained by applying the quasilocalized charge approximation (QLCA) formalism, while numerical data are generated by microcanonical molecular dynamics simulations. The dispersions and polarizations of the collective excitations obtained through both of these methods are compared and discussed in detail. We find that the QLCA method is, in general, very satisfactory, but that there are phenomena not covered by the QLCA. In particular, by analyzing the dynamical longitudinal and transverse current fluctuation spectra we discover the existence of a structure not related to the collective mode spectra. This also provides insight into the long-standing problem of the gap frequency discrepancy, observed in strongly coupled layered systems in earlier studies.
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Affiliation(s)
- Hong Pan
- Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - Gabor J Kalman
- Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - Peter Hartmann
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest, Hungary.,Center for Astrophysics, Space Physics and Engineering Research (CASPER), Baylor University, 100 Research Pkwy, Waco, Texas 76706, USA
| | - Zoltán Donkó
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, P.O. Box 49, H-1525 Budapest, Hungary
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Hartmann P, Donkó Z, Kalman GJ, Kyrkos S, Golden KI, Rosenberg M. Collective dynamics of complex plasma bilayers. PHYSICAL REVIEW LETTERS 2009; 103:245002. [PMID: 20366204 DOI: 10.1103/physrevlett.103.245002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Indexed: 05/29/2023]
Abstract
A classical dusty plasma experiment was performed using two different dust grain sizes to form a strongly coupled asymmetric bilayer (two closely spaced interacting monolayers) of two species of charged dust particles. The observation and analysis of the thermally excited particle oscillations revealed the collective mode structure and dispersion (wave propagation) in this system; in particular, the existence of the theoretically predicted k=0 energy (frequency) gap was verified. Equilibrium molecular-dynamics simulations were performed to emulate the experiment, assuming Yukawa-type interparticle interaction. The simulations and analytic calculations based both on lattice summation and on the quasilocalized charge approximation approach are in good agreement with the experimental findings and help in identifying and characterizing the observed phenomena.
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Affiliation(s)
- P Hartmann
- Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, H-1525 Budapest, P.O. Box 49, Hungary
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Jho YS, Park G, Chang CS, Pincus PA, Kim MW. Effects of dielectric discontinuities on two charged plates. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2007; 76:011920. [PMID: 17677507 DOI: 10.1103/physreve.76.011920] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Revised: 05/10/2007] [Indexed: 05/16/2023]
Abstract
Counterions in a biological system are charged in water and interact with charged macroions, which are generally made up of hydrocarbons. The dielectric difference between water and the hydrocarbon substrates occurs naturally, and may greatly affect the electrostatic properties of biological systems. Particularly for a slab geometry, bulk counterions that are dissolved in water are driven to the midplane of the slab because of their repulsive interaction with their image charges. The pressure between two charged plates becomes less repulsive since the low dielectric constant of the hydrocarbon substrate creates stronger association between counterions and surface charges as compared to the case of no dielectric discontinuity.
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Affiliation(s)
- Y S Jho
- Department of Physics, Korea Advanced Institute of Science and Technology, Yuseong-Gu, Daejeon, Korea.
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Jho YS, Park G, Chang CS, Pincus P, Kim MW. Interaction between two inhomogeneously charged parallel surfaces in the strong coupling regime. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 73:021502. [PMID: 16605337 DOI: 10.1103/physreve.73.021502] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2005] [Revised: 11/14/2005] [Indexed: 05/08/2023]
Abstract
The counterion density profile and pressure between two inhomogenously charged parallel plates are analyzed analytically and numerically in the strong-coupling regime. Point charges are used and the surface charges are immobile. It is found that when the surface charge distribution is inhomogeneous, the charge coupling effect becomes stronger, the counterion spatial distribution is more localized toward the plate surfaces, and, thus, the pressure between two plates becomes lower than in the case when the surface charge distribution is homogeneous.
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Affiliation(s)
- Y S Jho
- Department of Physics, Korea Advanced Institute of Science and Technology, Yuseong-Gu, Daejeon, Korea 305-701.
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Golden KI, Mahassen H, Kalman GJ, Senatore G, Rapisarda F. Dielectric matrix and plasmon dispersion in strongly coupled electronic bilayer liquids. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 71:036401. [PMID: 15903582 DOI: 10.1103/physreve.71.036401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2004] [Indexed: 05/02/2023]
Abstract
We develop a dielectric matrix and analyze plasmon dispersion in strongly coupled charged-particle bilayers in the T = 0 quantum domain. The formulation is based on the classical quasilocalized charge approximation (QLCA) and extends the QLCA formalism into the quantum domain. Its development, which parallels that of the two-dimensional companion paper [Phys. Rev. E 70, 026406 (2004)] by three of the authors, generalizes the single-layer scalar formalism therein to a bilayer matrix formalism. Using pair correlation function data generated from diffusion Monte Carlo simulations, we calculate the dispersion of the in-phase and out-of-phase plasmon modes over a wide range of high- r(s) values and layer separations. The out-of-phase spectrum exhibits an exchange-correlation induced long-wavelength energy gap in contrast to earlier predictions of acoustic dispersion softened by exchange and correlations. The energy gap is similar to what has been previously predicted for classical charged-particle bilayers and subsequently confirmed by recent molecular dynamics computer simulations.
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Affiliation(s)
- Kenneth I Golden
- Department of Mathematics and Statistics, University of Vermont, Burlington, 05405, USA.
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David N, Hooker SM. Molecular-dynamic calculation of the relaxation of the electron energy distribution function in a plasma. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2003; 68:056401. [PMID: 14682888 DOI: 10.1103/physreve.68.056401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2003] [Indexed: 05/24/2023]
Abstract
A molecular-dynamic (MD) code is used to calculate the temporal evolution of nonequilibrium electron distribution functions in plasmas. To the authors' knowledge, this is the first time that a molecular-dynamic code has been used to treat this problem using a macroscopic number of particles. The code belongs to the class of P3M (particle-particle-particle-mesh) codes. Since the equations solved by the MD code are fundamental, this approach avoids several assumptions that are inherent to alternative methods. For example, the initial energy distribution can be arbitrary, and there is no need to assume a value for the Coulomb logarithm. The advantages of the MD code are illustrated by comparing its results with those of Monte Carlo and Fokker-Planck codes with a set of plasma parameters for which the Fokker-Planck calculation is shown to give incorrect results. As an example, we calculate the relaxation of the electron energy distribution produced by optical field ionization of a mixed plasma containing argon and hydrogen.
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Affiliation(s)
- N David
- Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom
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Donkó Z, Kalman GJ, Hartmann P, Golden KI, Kutasi K. Dynamical structure functions, collective modes, and energy gap in charged-particle bilayers. PHYSICAL REVIEW LETTERS 2003; 90:226804. [PMID: 12857333 DOI: 10.1103/physrevlett.90.226804] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2002] [Revised: 03/06/2003] [Indexed: 05/24/2023]
Abstract
The dynamical properties of strongly coupled charged-particle bilayers are investigated by molecular dynamics (MD) simulation and theoretical analysis. The spectra of the current correlation functions show the existence of two (in-phase and out-of-phase) longitudinal and two (in-phase and out-of-phase) transverse collective modes. The out-of-phase modes possess finite frequencies at wave numbers k-->0, confirming the existence of the predicted long-wavelength energy gap in the bilayer system. A theoretical model based on an extended Feynman ansatz for the dynamical structure functions provides predictions on the strength of the collective modes that are verified by the MD experiment.
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Affiliation(s)
- Z Donkó
- Research Institute for Solid State Physics and Optics of the Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary
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L wen H, Allahyarov E, Likos CN, Blaak R, Dzubiella J, Jusufi A, Hoffmann N, Harreis HM. Charged colloids, polyelectrolytes and biomolecules viewed as strongly coupled Coulomb systems. ACTA ACUST UNITED AC 2003. [DOI: 10.1088/0305-4470/36/22/301] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Ranganathan S, Johnson RE. Molecular dynamics study of a bilayer electron gas: single particle properties. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2003; 67:041201. [PMID: 12786347 DOI: 10.1103/physreve.67.041201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2002] [Indexed: 05/24/2023]
Abstract
The single-particle dynamical properties of a strongly coupled, classical, symmetric electronic bilayer system have been investigated by molecular dynamics simulation. Results for the velocity correlation function, the single-particle scattering function, and their respective Fourier transforms have been calculated, and their behavior, as a function of the interlayer separation d, has been analyzed. The single-particle scattering function in particular, shows dramatic effects when the bilayer attains a staggered square lattice structure. This occurs when the interlayer separation is around 0.8a (a is the Wigner-Seitz radius), where our previous study showed a marked decrease in the diffusion coefficient.
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Affiliation(s)
- S Ranganathan
- Department of Physics, Royal Military College of Canada, Kingston, Ontario, Canada K7K 7B4
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Golden KI, Kalman GJ, Kyrkos S. Charged particle layers in the Debye limit. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2002; 66:031107. [PMID: 12366099 DOI: 10.1103/physreve.66.031107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2002] [Indexed: 05/23/2023]
Abstract
We develop an equivalent of the Debye-Hückel weakly coupled equilibrium theory for layered classical charged particle systems composed of one single charged species. We consider the two most important configurations, the charged particle bilayer and the infinite superlattice. The approach is based on the link provided by the classical fluctuation-dissipation theorem between the random-phase approximation response functions and the Debye equilibrium pair correlation function. Layer-layer pair correlation functions, screened and polarization potentials, static structure functions, and static response functions are calculated. The importance of the perfect screening and compressibility sum rules in determining the overall behavior of the system, especially in the r--> infinity limit, is emphasized. The similarities and differences between the quasi-two-dimensional bilayer and the quasi-three-dimensional superlattice are highlighted. An unexpected behavior that emerges from the analysis is that the screened potential, the correlations, and the screening charges carried by the individual layers exhibit a marked nonmonotonic dependence on the layer separation.
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Affiliation(s)
- Kenneth I Golden
- Department of Mathematics and Statistics, University of Vermont, Burlington, Vermont 05401-1455, USA.
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Ranganathan S, Johnson RE, Pathak KN. Molecular dynamics study of diffusion in a bilayer electron gas. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2002; 65:051203. [PMID: 12059541 DOI: 10.1103/physreve.65.051203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2001] [Indexed: 05/23/2023]
Abstract
Molecular dynamics simulations of strongly coupled, classical electronic bilayers, interacting through the Coulomb potential, have been produced and studied. Values of the plasma coupling parameter Gamma between 10 and 80 and interlayer separations d from 0.1 to 3.0, (in units of Wigner-Seitz radius), were considered. The simulation results were used to calculate the intralayer and interlayer pair correlation functions and self-diffusion of charged particles in this system. The variation of self-diffusion with Gamma and d has been analyzed, and it is found that for the largest value of Gamma, the diffusion coefficient does not increase monotonically with layer separation, but has a distinct minimum for values of d slightly less than 1.
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Affiliation(s)
- S Ranganathan
- Department of Physics, Royal Military College of Canada, Kingston, Ontario, Canada K7K 7B4
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