Implications of many-body forces for equations of state at high pressure

1992 ◽  
Vol 339 (1654) ◽  
pp. 395-402 ◽  
Keyword(s):  
High Pressure ◽  
Equations Of State ◽  
Closed Shell ◽  
Molecular Orbital Calculations ◽  
Many Body ◽  
Detonation Products ◽  
Body Forces ◽  
Three Body ◽  
Body Potential ◽  
Many Body Interactions

In this paper we review our recent work concerned with assessing the significance of many-body forces for short-range interactions of closed shell atoms and molecules. Ab initio molecular orbital calculations (of the supermolecule type) have been carried out to determine three-body potentials for the following species: He, Ne, H 2 , N 2 , CO and CO 2 . For He, Ne, H 2 and N 2 we have also carried out calculations of the four-body potential for a limited number of orientations. These studies show that, for all these species, there are significant deviations from pair-wise additivity at short separations. The effect of these many-body interactions on the equation of state for dense fluids (such as detonation products) is being investigated by Monte Carlo simulation, and recent results for high-pressure helium are described.

Data-Driven Many-Body Models with Chemical Accuracy for CH4/H2O Mixtures

2020 ◽  
Author(s):  
Marc Riera ◽  
Alan Hirales ◽  
Raja Ghosh ◽  
Francesco Paesani
Keyword(s):  
Liquid Phase ◽  
Quantitative Description ◽  
Liquid Mixtures ◽  
Many Body ◽  
Energy Functions ◽  
Potential Energy Functions ◽  
Dynamics Simulations ◽  
Body Potential ◽  
Small Clusters ◽  
Many Body Interactions

<div> <div> <div> <p>Many-body potential energy functions (PEFs) based on the TTM-nrg and MB-nrg theoretical/computational frameworks are developed from coupled cluster reference data for neat methane and mixed methane/water systems. It is shown that that the MB-nrg PEFs achieve subchemical accuracy in the representation of individual many-body effects in small clusters and enables predictive simulations from the gas to the liquid phase. Analysis of structural properties calculated from molecular dynamics simulations of liquid methane and methane/water mixtures using both TTM-nrg and MB-nrg PEFs indicates that, while accounting for polarization effects is important for a correct description of many-body interactions in the liquid phase, an accurate representation of short-range interactions, as provided by the MB-nrg PEFs, is necessary for a quantitative description of the local solvation structure in liquid mixtures. </p> </div> </div> </div>

scholarly journals Atomic-state-dependent screening model for hot and warm dense plasmas

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Fuyang Zhou ◽  
Yizhi Qu ◽  
Junwen Gao ◽  
Yulong Ma ◽  
Yong Wu ◽  
...  
Keyword(s):  
Radiation Transport ◽  
Atomic State ◽  
Many Body ◽  
Dense Plasmas ◽  
Screening Model ◽  
State Dependent ◽  
Recombination Processes ◽  
Three Body ◽  
Many Body Interactions ◽  
Body Recombination

AbstractAn ion embedded in warm/hot dense plasmas will greatly alter its microscopic structure and dynamics, as well as the macroscopic radiation transport properties of the plasmas, due to complicated many-body interactions with surrounding particles. Accurate theoretically modeling of such kind of quantum many-body interactions is essential but very challenging. In this work, we propose an atomic-state-dependent screening model for treating the plasmas with a wide range of temperatures and densities, in which the contributions of three-body recombination processes are included. We show that the electron distributions around an ion are strongly correlated with the ionic state studied due to the contributions of three-body recombination processes. The feasibility and validation of the proposed model are demonstrated by reproducing the experimental result of the line-shift of hot-dense plasmas as well as the classical molecular dynamic simulations of moderately coupled ultra-cold neutral plasmas. Our work opens a promising way to treat the screening effect of hot and warm dense plasma, which is a bottleneck of those extensive studies in high-energy-density physics, such as atomic processes in plasma, plasma spectra and radiation transport properties, among others.

Equation of state for the detonation products of energetic materials

2021 ◽  
Vol 11 (8) ◽  
pp. 1269-1287
Author(s):  
Xiangyu Huo ◽  
Li Zhang ◽  
Mingli Yang
Keyword(s):  
Artificial Intelligence ◽  
High Pressure ◽  
Computer Simulations ◽  
Energetic Materials ◽  
Equations Of State ◽  
Experiment Study ◽  
Detonation Products ◽  
Main Approach ◽  
Practical Applications ◽  
Integrated Theory

Energetic materials (EMs) are one of the necessities in many military and civilian applications. Measuring the thermodynamic behaviors of detonation products of EMs at high temperature and high pressure, their equations of state (EOSs) not only serve as a basis in the design of novel materials, but also provide valuable information for their practical applications. The EOS study has a long history, but keeps moving all the time. Various EMs have been developed, the EOS of detonation products provides abundant information in the thermochemistry, hydromechanics and detonation physics, which in turn feedbacks the development of novel EMs and their EOSs. With the development of experimental techniques and computer simulations, many EOSs have been proposed for various explosives in recent years. While experiments keep their fundamental roles, integrated theory-experiment study has become the main approach to the EOS establishment for novel EMs. Moreover, computer simulations based on interatomic and/or intermolecular interaction will have great potential in the future when big data and artificial intelligence are introduced into the field.

scholarly journals Full reconstruction of simplicial complexes from binary time-series data

2021 ◽  
Author(s):  
Huan Wang ◽  
Chuang Ma ◽  
Han-Shuang Chen ◽  
Ying-Cheng Lai ◽  
Hai-Feng Zhang
Keyword(s):  
Time Series ◽  
Time Series Data ◽  
Simplicial Complexes ◽  
Series Data ◽  
Many Body ◽  
Stochastic Disturbance ◽  
Binary Time Series ◽  
Full Reconstruction ◽  
Three Body ◽  
Many Body Interactions

Abstract Previous efforts on data-based reconstruction focused on complex networks with pairwise or two-body interactions. There is a growing interest in networks with high-order or many-body interactions, raising the need to reconstruct such networks based on observational data. We develop a general framework combining statistical inference and expectation maximization to fully reconstruct 2-simplicial complexes with two- and three-body interactions based on binary time-series data from social contagion dynamics. We further articulate a two-step scheme to improve the reconstruction accuracy while significantly reducing the computational load. Through synthetic and real-world 2-simplicial complexes, we validate the framework by showing that all the connections can be faithfully identified and the full topology of the 2-simplicial complexes can be inferred. The effects of noisy data or stochastic disturbance are studied, demonstrating the robustness of the proposed framework.

scholarly journals Lattice Dynamics of the High Tc Superconductor ErBa2Cu3O7

1994 ◽  
Vol 47 (1) ◽  
pp. 103 ◽  
Author(s):  
S Mohan ◽  
R Kannan
Keyword(s):  
Lattice Dynamics ◽  
Many Body ◽  
New Approach ◽  
High Tc ◽  
High Tc Superconductor ◽  
Zone Centre ◽  
Three Body ◽  
Many Body Interactions ◽  
Good Agreement ◽  
Infrared Data

The lattice dynamics of the high Tc superconductor ErBa2Cu307 have been investigated in detail with a modified three-body force shell model. The model accounts for the effect of many-body interactions in the lattice potential. The aim of the present work is to treat the various interactions between the ions in generalised way without making them numerically equal. The values of the phonon frequencies calculated at the zone centre by this new approach are in good agreement with the available Raman and infrared data.

scholarly journals Low-order many-body interactions determine the local structure of liquid water

2019 ◽  
Vol 10 (35) ◽  
pp. 8211-8218 ◽  
Author(s):  
Marc Riera ◽  
Eleftherios Lambros ◽  
Thuong T. Nguyen ◽  
Andreas W. Götz ◽  
Francesco Paesani
Keyword(s):  
Liquid Water ◽  
Local Structure ◽  
Quantum Effects ◽  
Many Body ◽  
Three Body ◽  
Many Body Interactions ◽  
Nuclear Quantum Effects ◽  
Structure Of Liquid ◽  
Low Order

Two-body and three-body energies, modulated by higher-body terms and nuclear quantum effects, determine the structure of liquid water and require sub-chemical accuracy that is achieved by the MB-pol model but not by existing DFT functionals.

Atomistic simulation of a high-pressure phase of AgI using a three-body potential

1999 ◽  
Vol 112 (1) ◽  
pp. 49-54 ◽  
Author(s):  
W. Sekkal ◽  
A. Laref ◽  
A. Zaoui ◽  
H. Aourag ◽  
M. Certier
Keyword(s):  
High Pressure ◽  
Atomistic Simulation ◽  
High Pressure Phase ◽  
Three Body ◽  
Body Potential ◽  
Pressure Phase

GOLD DEPOSITION ON GaAs(001) SURFACES: MOLECULAR-DYNAMICS SIMULATIONS

2002 ◽  
Vol 13 (06) ◽  
pp. 759-769 ◽  
Author(s):  
ŞAKIR ERKOÇ ◽  
LYNDA AMIROUCHE ◽  
LEILA ROUAIGUIA
Keyword(s):  
Molecular Dynamics ◽  
Gold Atom ◽  
Potential Energy Function ◽  
Gold Deposition ◽  
Many Body ◽  
Atomic Interactions ◽  
Dynamics Simulations ◽  
Three Body ◽  
Body Potential ◽  
Different Characteristics

We have simulated the gold deposition on arsenic and gallium terminated GaAs(001) surfaces at low and room temperatures. It has been found that gallium terminated surface is relatively less stable in comparison to the arsenic terminated surface. On the other hand, a single gold adatom on the surface has different characteristics than full coverage gold atoms on the surface; a single gold atom diffuses into the surface at room temperature. Simulations have been performed by considering classical molecular-dynamics technique using an empirical many-body potential energy function comprising two- and three-body atomic interactions.

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