Molecular dynamics simulation of interhalogen compounds. 1. Liquid chlorine trifluoride (ClF3): structure and thermodynamics

1992 ◽  
Vol 70 (1) ◽  
pp. 34-38 ◽  
Author(s):  
Ramesh K. Wadi ◽  
Vivek Saxena
Keyword(s):  
Molecular Dynamics ◽  
Thermodynamic Properties ◽  
Md Simulation ◽  
Pair Potential ◽  
Liquid Structure ◽  
Spectroscopic Studies ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Self Diffusion ◽  
Laser Raman

The results of a molecular dynamics (MD) simulation study of liquid chlorine trifluoride (ClF3) at 217, 260, and 287 K are reported. The cubic simulation cell consists of 108 ClF3 molecules assumed to be interacting via site–site Lennard–Jones 12–6 pair potential. The parameters for F–F and Cl–Cl interaction are the same as used for the simulation of F2, and Cl2, respectively, and those for the Cl–F cross interaction are calculated using Lorentz–Berthelot rules. These results are then used to calculate various radial distribution functions characteristic of the liquid structure. Thermodynamic properties, namely, configurational energy, constant volume specific heat, and internal pressure are also reported. The time-dependent properties, mean square force and torque, self diffusion coefficient, and the quantum corrections to the free energy, were also obtained. The dimer configuration drawn based on the observed contact distances was found to be in good agreement with the results of matrix isolation infrared and laser Raman spectroscopic studies. Keywords: MD simulation, interhalogens, liquid structure, thermodynamic properties.

scholarly journals Investigation of Microscopic Structure and Ion Dynamics in Liquid Li(Na, K)EutecticCl Systems by Molecular Dynamics Simulation

2018 ◽  
Vol 8 (10) ◽  
pp. 1874 ◽  
Author(s):  
Jie Wu ◽  
Jia Wang ◽  
Haiou Ni ◽  
Guimin Lu ◽  
Jianguo Yu
Keyword(s):  
Molecular Dynamics ◽  
Ionic Conductivity ◽  
Shear Viscosity ◽  
Ion Pairs ◽  
Liquid Structure ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Molten Chloride ◽  
Ion Clusters ◽  
Self Diffusion

Molten chloride salts are the main components in liquid metal batteries, high-temperature heat storage materials, heat transfer mediums, and metal electrolytes. In this paper, interest is centered on the influence of the LiCl component and temperature on the local structure and transport properties of the molten LiCl-NaCl-KCl system over the temperature range of 900 K to 1200 K. The liquid structure and properties have been studied across the full composition range by molecular dynamics (MD) simulation of a sufficient length to collect reliable values, such as the partial radial distribution function, angular distribution functions, coordination numbers distribution, density, self-diffusion coefficient, ionic conductivity, and shear viscosity. Densities obtained from simulations were underestimated by an average 5.7% of the experimental values. Shear viscosities and ionic conductivity were in good agreement with the experimental data. The association of all ion pairs (except for Li-Li and Cl-Cl) was weakened by an increasing LiCl concentration. Ion clusters were formed in liquids with increasing temperatures. The self-diffusion coefficients and ionic conductivity showed positive dependences on both LiCl concentration and temperature, however, the shear viscosity was the opposite. By analyzing the hydrodynamic radii of each ion and the coordination stability of cation-anion pairs, it was speculated that ion clusters could be the cation-anion coordinated structure and affected the macro properties.

Molecular Dynamics Simulation of Molten Alkali Nitrates

2001 ◽  
Vol 56 (5) ◽  
pp. 337-341 ◽  
Author(s):  
G. Vöhringer ◽  
J. Richter
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficients ◽  
Short Range ◽  
Spin Echo ◽  
Isotope Effects ◽  
Pair Potential ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Self Diffusion ◽  
Transport Effects

Abstract Molecular dynamics (MD) simulations have been performed for several pure alkali nitrate melts. Special attention was paid to the examination of the interaction potential: macroscopic quantities like pressure were calculated and compared with real values. To improve the results the commonly used potential for alkali nitrates (Coulomb pair potential and Born-type repulsion) has been extended by a short-range-attraction term to meet the real behaviour of the liquid. With these improved potentials, simulations of pure LiNO3, NaNO3, KNO3, and RbNO3 have been performed with special regard to the influence of size and mass of the cations on the transport effects to show analogies to isotope effects. The calculated self diffusion coefficients (SDC) have been compared to results obtained with the NMR spin echo method.

Structure and Dynamics of NaCl in Methanol. A Molecular Dynamics Study

1991 ◽  
Vol 46 (10) ◽  
pp. 887-897 ◽  
Author(s):  
D. Marx ◽  
K. Heinzinger ◽  
G. Pálinkás ◽  
I. Bakó
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficients ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Nacl Solution ◽  
Geometrical Arrangement ◽  
Self Diffusion ◽  
Site Model ◽  
Structure And Dynamics ◽  
Dynamical Properties

AbstractA recently developed flexible three-site model for methanol was employed to perform a Molecular Dynamics simulation of a 0.6 molal NaCl solution. The ion-methanol and ion-ion potential functions were derived from ab initio calculations. The structural properties of the solution are discussed on the basis of radial and angular distribution functions, the orientation of the methanol molecules, and their geometrical arrangement in the solvation shells of the ions. The dynamical properties of the solution - like self-diffusion coefficients, hindered translations, librations, and internal vibrations of the methanol molecules - are calculated from various autocorrelation functions.

Au–Fe nanoparticles visited by MD simulation: structural and thermodynamic properties affected by chemical composition

2018 ◽  
Vol 42 (12) ◽  
pp. 9666-9675 ◽  
Author(s):  
Hamed Akbarzadeh ◽  
Esmat Mehrjouei ◽  
Amir Nasser Shamkhali ◽  
Mohsen Abbaspour ◽  
Sirous Salemi ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Chemical Composition ◽  
Molecular Dynamics Simulation ◽  
Thermodynamic Properties ◽  
Thermodynamic Stability ◽  
Md Simulation ◽  
Dynamics Simulation ◽  
Core Shell ◽  
Fe Nanoparticles ◽  
Melting Mechanism

In this work, Fe–Au nanoalloys and Fe@Au core–shell nanoclusters are investigated via classical molecular dynamics simulation to determine the effect of their composition on their thermodynamic stability and melting mechanism.

Molecular Dynamics Study of a Lithium Ion in Ammonia

1988 ◽  
Vol 43 (6) ◽  
pp. 572-582 ◽  
Author(s):  
S. V. Hannongbua ◽  
T. Ishida ◽  
E. Spohr ◽  
K. Heinzinger
Keyword(s):  
Molecular Dynamics ◽  
Lithium Ion ◽  
Solvation Shell ◽  
Distribution Functions ◽  
Dynamics Simulation ◽  
Self Diffusion ◽  
Average Temperature ◽  
Self Diffusion Coefficient ◽  
Flexible Model ◽  
N Vector

Abstract A Molecular Dynamics simulation of a solution of one Li+ in 215 NH3 molecules has been performed at an average temperature of 235 K. A newly developed flexible model for NH3 is employed and the Li +−NH3 interactions are derived from ab initio calculations. The structure of the solution is described by radial distribution functions and the orientation of the molecules. A solvation number of six is found for Li+ and a strong preference of the solvation shell molecules exists for an orientation where the Li + −N vector and the dipole moment direction of NH3 are parallel. The self-diffusion coefficient, the hindered translational motions and librations are calculated separately for the ammonia molecules in the solvation shell and in the bulk. The effect of Li + on intramolecular geometry and vibrations is reported.

Molecular dynamics simulation of interhalogen compounds using two potential models 2. Liquid bromine trifluoride (BrF3) — structure and thermodynamics

1993 ◽  
Vol 71 (12) ◽  
pp. 2189-2193 ◽  
Author(s):  
Vivek Saxena
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Pair Potential ◽  
Dynamics Simulation ◽  
Gaseous State ◽  
Self Diffusion ◽  
Lennard Jones ◽  
Interaction Terms ◽  
Liquid Bromine ◽  
Bromine Trifluoride

This paper reports on the molecular dynamics simulation results of liquid bromine trifluoride (BrF3) at 299, 315, and 363 K. We have assumed that the molecules interact via Lennard–Jones 12–6 site–site pair potential and Lennard–Jones site–site + fractional charges over atomic sites. Lennard–Jones potential parameters of Singer et al. (Mol. Phys. 33, 1757 (1977)) have been used for Br–Br, and F–F interactions and cross interaction terms are calculated using Lorentz–Berthelot mixing rules. Fractional charges are assigned to reproduce the experimentally determined gaseous-state molecular dipole moment. Various structural and thermodynamic properties for liquid state are reported and compared in detail with results from diffraction studies (Mittkin et al. J. Struct. Chem. 28, 60 (1987)). Some mechanical properties such as mean-square force and torque, self-diffusion coefficient have also been calculated. The repulsive part of the proposed atom–atom pair potential is a good approximation since both molecular configurations are in good agreement with experimental results.

Translational and rotational dynamics in supercritical methanol from molecular dynamics simulation

2004 ◽  
Vol 76 (1) ◽  
pp. 203-213 ◽  
Author(s):  
Michalis Chalaris ◽  
J. Samios
Keyword(s):  
Molecular Dynamics ◽  
Diffusion Coefficients ◽  
Md Simulation ◽  
Time Correlation ◽  
The Self ◽  
Dynamics Simulation ◽  
Supercritical Methanol ◽  
Reorientational Motion ◽  
Self Diffusion ◽  
Theoretical Predictions

The purpose of this paper is to review our latest molecular dynamics (MD) simulation studies on the temperature and density dependence of the translational and reorientational motion in supercritical (SC) methanol. In the present treatment, Jorgensen's [W. L. Jorgensen. J. Phys. Chem. A102, 8641 (1998)] transferable potential model, tested in a recent MD study of hydrogen bonds in this fluid [M. Chalaris and J. Samios, J. Phys. Chem. B103, 1161 (1999)], was employed to simulate the dynamics of the system. The simulations were performed in the canonical (NVT) ensemble along the isotherms 523, 623, and 723 K and densities corresponding to the pressures from 10 to 30 MPa. Several dynamical properties of the fluid have been obtained and analyzed in terms of appropriate time-correlation functions (CFs). With respect to the translational dynamics, the self-diffusion coefficients obtained have been used to test the applicability of the well-known Chapman-Enskog kinetic theory. We have found that the theoretical predictions for the self-diffusion coefficients are only in qualitative agreement with the MD results over the whole temperature and density range studied. Finally, the inspection of the reorientational CFs and their corresponding correlation times lead to the conclusion that the reorientational motion of the SC methanol molecules in the sample is anisotropic.

Some Properties of Molten KCl at High Density Studied by MD Simulation

1981 ◽  
Vol 36 (10) ◽  
pp. 1106-1111 ◽  
Author(s):  
Ryuzo Takagi ◽  
Isao Okada ◽  
Kazutaka Kawamura
Keyword(s):  
Molecular Dynamics ◽  
Monte Carlo ◽  
Thermodynamic Properties ◽  
Diffusion Coefficients ◽  
Md Simulation ◽  
Ambient Pressure ◽  
The Self ◽  
Self Diffusion ◽  
Dynamics Simulations ◽  
Good Agreement

Molecular dynamics simulations of molten KCl have been performed at 1173 K with the molar volumes of 52.0 (the value under ambient pressure), 50.0, 48.0 and 45.0 cm3 mol-1 . Some thermodynamic properties at higher densities have been evaluated, which are generally in good agreement with the experimentally obtained ones and Monte Carlo results. Both at normal and higher densities, the self-exchange velocities of neighbouring unlike ions (SEV) are found to be proportional to the internal mobilities with nearly the same constant as derived previously for molten LiCl, RbCl and their 1 : 1 mixture. Calculated transport properties such as the SEV and the self-diffusion coefficients considerably decrease with increasing density, while the configuration does not change much.

scholarly journals Molecular Dynamics Simulation on the Interaction between Palygorskite Coating and Linear Chain Alkane Base Lubricant

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 286
Author(s):  
Jin Zhang ◽  
Lv Yang ◽  
Yue Wang ◽  
Huaichao Wu ◽  
Jiabin Cai ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Structural Changes ◽  
Molecular Diffusion ◽  
Linear Chain ◽  
Interfacial Interaction ◽  
Dynamics Simulation ◽  
Electrostatic Energy ◽  
Experimental Development ◽  
Practical Applications ◽  
Self Diffusion

Molecular dynamics (MD) simulations were conducted to investigate the interactions between a palygorskite coating and linear chain alkanes (dodecane C12, tetradecane C14, hexadecane C16, and octadecane C18), representing base oils in this study. The simulation models were built by placing the alkane molecules on the surface of the palygorskite coating. These systems were annealed and geometrically optimized to obtain the corresponding stable configurations, followed by the analysis of the structural changes occurring during the MD process. The interfacial interaction energies, mean square displacements, and self-diffusion coefficients of the systems were evaluated to characterize the interactions between base lubricant molecules and palygorskite coating. It was found that the alkanes exhibited self-arrangement ability after equilibrium. The interfacial interaction was attractive, and the electrostatic energy was the main component of the binding energy. The chain length of the linear alkanes had a significant impact on the intensity of the interfacial interactions and the molecular diffusion behavior. Moreover, the C12 molecule exhibited higher self-diffusion coefficient values than C14, C16 and C18. Therefore, it could be the best candidate to form an orderliness and stable lubricant film on the surface of the palygorskite coating. The present work provides new insight into the optimization of the structure and composition of coatings and lubricants, which will guide the experimental development of these systems for practical applications.

scholarly journals Molecular dynamics simulation of sI methane hydrate under compression and tension

2020 ◽  
Vol 18 (1) ◽  
pp. 69-76
Author(s):  
Qiang Wang ◽  
Qizhong Tang ◽  
Sen Tian
Keyword(s):  
Molecular Dynamics ◽  
Methane Hydrate ◽  
Fracture Process ◽  
Md Simulation ◽  
Maximum Stress ◽  
Dynamics Simulation ◽  
Tensile Fracture ◽  
Maximum Compressive Stress ◽  
Motion State ◽  
Stress States

AbstractMolecular dynamics (MD) analysis of methane hydrate is important for the application of methane hydrate technology. This study investigated the microstructure changes of sI methane hydrate and the laws of stress–strain evolution under the condition of compression and tension by using MD simulation. This study further explored the mechanical property and stability of sI methane hydrate under different stress states. Results showed that tensile and compressive failures produced an obvious size effect under a certain condition. At low temperature and high pressure, most of the clathrate hydrate maintained a stable structure in the tensile fracture process, during which only a small amount of unstable methane broke the structure, thereby, presenting a free-motion state. The methane hydrate cracked when the system reached the maximum stress in the loading process, in which the maximum compressive stress is larger than the tensile stress under the same experimental condition. This study provides a basis for understanding the microscopic stress characteristics of methane hydrate.

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