Reflecting Boundary Conditions for Classical and Quantum Molecular Dynamics Simulations of Nonideal Plasmas

Lavrinenko, Ya S; Морозов, И. В.; Valuev, Ilya

doi:10.1002/ctpp.201500139

Cited by 10 publications

(11 citation statements)

References 38 publications

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“…As shown by Lavrinenko et al, the influence of the confinement on the properties of the simulated system decreases with the system size, but has to be controlled for each of the calculated property. The energies are less sensitive to the confinement size and wall steepness and converge at system sizes of N e ≈ 60.…”

Section: Wpmd‐dft Methodsmentioning

confidence: 96%

“…The unlimited broadening of the Gaussian wave packets and underestimation of the electron–electron and electron–ion collision frequencies are known to be the major problems of the WPMD method when applied to many‐particle systems with homogeneous density, for example, plasma systems. In our earlier work, we proposed the use of a 3D confinement potential to properly constrain the wave packet broadening without applying any other unphysical restrictions on the wave packet localization:

U_{wall} (x) = \{\begin{matrix} left \\ a {(()||, x, - L false/ 2)}^{2}, & ∣ x ∣ > L / 2, \\ 0, & ∣ x ∣ \leq L / 2, \end{matrix}

where

L = n_{normale}^{- 1 / 3} N_{normale}

is the simulation box edge. The infinite WP broadening is directly related to the infinite statistical sum in an unconstrained system and does not appear in the confined system.…”

Section: Wpmd‐dft Methodsmentioning

confidence: 99%

“…The constant a was chosen to correspond to the harmonic wall, which for pure harmonic confinement would result in the ground eigen state with the width of L /20. Following the discussion by Lavrinenko et al, for comparison of WPMD/WPMC energies with other methods such as PIMC, we also correct the total energy of the WPMD system for the electron width degree of freedom equilibrium oscillations − N e kT .…”

Section: Wpmd‐dft Methodsmentioning

confidence: 99%

“…These issues are addressed in the WPMD‐DFT model which is introduced in this paper. To avoid wave packet spreading and the introduction of unphysical wave packet width constraints, we use a confined model system as proposed recently . The exact exchange approach provided by AWPMD is replaced by the exchange‐correlation functional in the frame of DFT.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Wave packet molecular dynamics–density functional theory method for non‐ideal plasma and warm dense matter simulations

Lavrinenko

Морозов

Valuev

2019

Contributions to Plasma Physics

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A new wave packet molecular dynamics–density functional theory (WPMD‐DFT) method is proposed for atomistic simulations of non‐ideal plasma and warm dense matter. The method is based on the WPMD approach, where the electronic exchange and correlation effects are treated using an additional energy term taken from DFT. This term is calculated by integration over the mesh values of the wave packet density. The local density approximation is implemented so far. WPMD‐DFT is meant as a replacement for the anti‐symmetrized WPMD (AWPMD) method which is more time consuming and lacks electron correlation. In this paper, we compare the results obtained by WPMD‐DFT, WPMD, AWPMD, classical molecular dynamics, and path integral Monte Carlo methods for the internal energy of the hydrogen plasma in the temperature range 10–50 kK and electron number density from 1020 to 1024 cm−3. We also demonstrate the ability to handle the simultaneous dynamics of electrons and ions by calculating the electron–ion temperature relaxation. The scalability of the WPMD‐DFT method with the number of electrons is shown for implementations in central processing unit and graphical processing unit.

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Section: Wpmd‐dft Methodsmentioning

confidence: 96%

U_{wall} (x) = \{\begin{matrix} left \\ a {(()||, x, - L false/ 2)}^{2}, & ∣ x ∣ > L / 2, \\ 0, & ∣ x ∣ \leq L / 2, \end{matrix}

where

L = n_{normale}^{- 1 / 3} N_{normale}

is the simulation box edge. The infinite WP broadening is directly related to the infinite statistical sum in an unconstrained system and does not appear in the confined system.…”

Section: Wpmd‐dft Methodsmentioning

confidence: 99%

Section: Wpmd‐dft Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Wave packet molecular dynamics–density functional theory method for non‐ideal plasma and warm dense matter simulations

Lavrinenko

Морозов

Valuev

2019

Contributions to Plasma Physics

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“…Multiple approaches to counter this expansion has been proposed, see Refs. [78,82,85]. Currently, we employ an additional potential energy term on the form…”

Section: Confining Potentialsmentioning

confidence: 99%

Development of a new quantum trajectory molecular dynamics framework

Svensson¹,

Campbell²,

Graziani³

et al. 2022

Preprint

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An extension to the wave packet description of quantum plasmas is presented, where the wave packet can be elongated in arbitrary directions. A generalised Ewald summation is constructed for the wave packet models accounting for long-range Coulomb interactions and fermionic effects are approximated by purpose-built Pauli potentials, self-consistent with the wave packets used. We demonstrate its numerical implementation with good parallel support and close to linear scaling in particle number, used for comparisons with the more common wave packet employing isotropic states. Ground state and thermal properties are compared between the models with differences occurring primarily in the electronic subsystem. Especially, the electrical conductivity of dense hydrogen is investigated where a 15% increase in DC conductivity can be seen in our wave packet model compared to other models.

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Electron–ion temperature relaxation in nonideal plasmas: High accuracy classical molecular dynamics simulations

Lavrinenko,

Morozov,

Valuev

2024

Contributions to Plasma Physics

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In this work, we prepare a simulation framework for a high‐accuracy numerical study of electron–ion temperature relaxation in nonideal (strongly coupled) plasmas. The existing relaxation rate theories require either parameter selection or some pre‐knowledge of the electron–ion correlation functions and effective interaction potentials. This makes non‐equilibrium classical and quantum molecular dynamics simulations a crucial stage in the study of energy transfer rates. We begin by revisiting the classical molecular dynamics simulations of a system of equally charged particles with different masses on a neutralizing background. We accurately simulate this simple ab‐initio (parameterless) system with controlled precision in terms of number of particles, mass ratio, and energy convergence. The predictions for the equally charged system are compared to the previous simulations and theories, which are reproduced with higher accuracy. We also perform a series of classical molecular dynamics simulations of the system of oppositely charged particles with the corrected Kelbg potential based on the quantum statistical approach. We analyze the differences and similarities between the same‐charge and opposite‐charge systems. Some remarks about the forthcoming application of quantum simulations with the help of WPMD or WPMD‐DFT methods are given.

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Reflecting Boundary Conditions for Classical and Quantum Molecular Dynamics Simulations of Nonideal Plasmas

Cited by 10 publications

References 38 publications

Wave packet molecular dynamics–density functional theory method for non‐ideal plasma and warm dense matter simulations

Wave packet molecular dynamics–density functional theory method for non‐ideal plasma and warm dense matter simulations

Development of a new quantum trajectory molecular dynamics framework

Electron–ion temperature relaxation in nonideal plasmas: High accuracy classical molecular dynamics simulations

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