Classical density functional approach to depletion interaction of Lennard-Jones binary mixtures

2021 ◽  
Author(s):  
Yue Chen ◽  
Wei Chen ◽  
Xiaosong Chen
Keyword(s):  
Bulk Density ◽  
Density Functional ◽  
Binary Systems ◽  
Hard Spheres ◽  
Distribution Functions ◽  
Functional Formalism ◽  
Depletion Interaction ◽  
Lennard Jones ◽  
Depletion Force ◽  
Binary Fluid Mixtures

Abstract In this article, we apply classical density functional theory to investigate the characteristics of depletion interaction in Lennard-Jones (LJ) binary fluid mixtures. First of all, in order to confirm the validity of our adopted density functional formalism, we calculate the radial distribution functions with theoretical approach and compare them with results obtained by molecular dynamics simu- lation. Then this approach is applied to the case of two colloids immersed in LJ solvent systems. We investigate the variation of depletion interaction with respect to the distance of two colloids in LJ binary systems. We find that depletion interaction may be attractive or repulsive, mostly depending on the bulk density of solvent and the temperature of binary system. For high bulk densities, the repulsive barrier of depletion force is remarkable when the total excluded volume of colloids touches each other and reaches a maximum. The height of repulsive barrier is related to the parameters of LJ potential and bulk density. Moreover, depletion force may exhibit attractive wells if the bulk density of solvent is low. The attractive well tends to appear when the surface-surface distance of colloids is half of the size of polymer and deepen with temperature lowering in a fixed bulk density. In contrast with the hard-spheres system, no oscillation of depletion potential around zero is observed.

Density-Functional Thermodynamic Perturbation Theory of Lennard-Jones Solids

1992 ◽  
Vol 278 ◽  
Author(s):  
Agathagelos Kyrlidis ◽  
Robert A. Brown
Keyword(s):  
Density Functional ◽  
Interatomic Potential ◽  
Structural Information ◽  
Hard Spheres ◽  
Energy Functional ◽  
Thermodynamic Perturbation Theory ◽  
Lennard Jones ◽  
Dependent Potential ◽  
Solid Liquid ◽  
Thermodynamic Perturbation

AbstractThe thermodynamics of a fcc hard spheres solid is accurately described by recent density-functional approximations. This state is used as a reference in a thermodynamic perturbation analysis for a density-functional theory of Lennard-Jones solids. The free energy functional incorporates liquid state structural information and a density dependent potential decomposition for the Lennard-Jones interatomic potential. The computed free energies of the solids compare very well with the predictions of atonlistic simulations. Solid-liquid coexistence is predicted consistently to within 15% of results of Monte Carlo simulations, over the temperature range 0.75 ≤ kT/c ε ≤ 10.

Evaluation of the Percus–Yevick Theory for Mixtures of Simple Liquids

1973 ◽  
Vol 51 (11) ◽  
pp. 1216-1226 ◽  
Author(s):  
E. W. Grundke ◽  
D. Henderson ◽  
R. D. Murphy
Keyword(s):  
Energy Equation ◽  
Geometrical Structure ◽  
Distribution Functions ◽  
Excess Properties ◽  
Simple Liquids ◽  
Binary Fluid ◽  
Fluid Mixtures ◽  
Lennard Jones ◽  
Binary Fluid Mixtures ◽  
Pair Distribution Functions

This paper reports zero-pressure excess properties of binary fluid mixtures of Lennard-Jones 6:12 molecules calculated from the Percus–Yevick (PY) theory and the energy equation. The PY theory, used this way, gives results that are in excellent agreement with simulation studies.In addition, results obtained from the compressibility equation are discussed for comparison. The geometrical structure of the mixture, as indicated by the PY pair distribution functions, is described. Error estimates are provided for the calculated excess properties.

Theory and calculation of colloidal depletion interaction

2018 ◽  
Vol 32 (18) ◽  
pp. 1840005 ◽  
Author(s):  
Hongru Ma
Keyword(s):  
Hard Sphere ◽  
Density Functional ◽  
Colloidal Particles ◽  
Hard Spheres ◽  
Effective Interaction ◽  
Density Functional Theory Method ◽  
Ratio Method ◽  
Colloidal System ◽  
Colloidal Systems ◽  
Depletion Interaction

Colloidal dispersion is composed of particles with size ranging from 1 nm to [Formula: see text]m dispersed in solvents. There are the volume exclusion interaction and other interactions between colloidal particles, of which the former interaction causes the depletion effect. When a big sphere is immersed in the colloidal system of small spheres, there is a depletion layer around the big sphere where the center of small sphere cannot enter. The depletion layers of two big spheres overlap if they are close to each other, increasing the free volume accessed by small spheres and thereby enlarging the entropy of the system. As a result, an effective interaction between the two big spheres is resulted from the change of entropy as a function of their distance, which is referred to as the depletion interaction. This paper first introduces the concept and scenario of the depletion interaction in colloidal systems. Then we briefly introduce various numerical or simulations methods of the depletion interaction of hard sphere systems, such as the acceptance ratio method, Wang–Landau method, and the density functional theory method. Taking the Asakura–Oosawa model as an example, we introduce a useful approximation method, Derjaguin approximation as well as the derivation of some approximate formula for the depletion interaction of different hardcore colloidal systems, such as between a pair of spheres in mono-disperse small spheres, between a hard sphere and a hard wall in a liquid of small spheres, and between a pair of hard spheres in a liquid of thin rods and thin disks.

scholarly journals The Effect of Topology on Phase Behavior under Confinement

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1220
Author(s):  
Arnout M. P. Boelens ◽  
Hamdi A. Tchelepi
Keyword(s):  
Phase Behavior ◽  
Density Functional ◽  
Capillary Condensation ◽  
Good Description ◽  
Functional Theory ◽  
Minkowski Functionals ◽  
First Order ◽  
Lennard Jones ◽  
And Topology ◽  
First Order Transition

This work studies how morphology (i.e., the shape of a structure) and topology (i.e., how different structures are connected) influence wall adsorption and capillary condensation under tight confinement. Numerical simulations based on classical density functional theory (cDFT) are run for a wide variety of geometries using both hard-sphere and Lennard-Jones fluids. These cDFT computations are compared to results obtained using the Minkowski functionals. It is found that the Minkowski functionals can provide a good description of the behavior of Lennard-Jones fluids down to small system sizes. In addition, through decomposition of the free energy, the Minkowski functionals provide a good framework to better understand what are the dominant contributions to the phase behavior of a system. Lastly, while studying the phase envelope shift as a function of the Minkowski functionals it is found that topology has a different effect depending on whether the phase transition under consideration is a continuous or a discrete (first-order) transition.

scholarly journals Effect of vacancy defects on the electronic transport properties of an Ag–ZnO–Pt sandwich structure

2021 ◽  
Vol 20 (2) ◽  
pp. 798-804
Author(s):  
G. R. Berdiyorov ◽  
F. Boltayev ◽  
G. Eshonqulov ◽  
H. Hamoudi
Keyword(s):  
Transport Properties ◽  
Electronic Transport ◽  
Density Functional ◽  
Practical Importance ◽  
Functional Formalism ◽  
Vacancy Defects ◽  
Electronic Transport Properties ◽  
Charge Localization ◽  
Metal Insulator Metal ◽  
Current Rectification

AbstractThe effect of zinc and oxygen vacancy defects on the electronic transport properties of Ag(100)–ZnO(100)–Pt(100) sandwich structures is studied using density functional theory in combination with the nonequilibrium Green’s functional formalism. Defect-free systems show clear current rectification due to voltage dependent charge localization in the system as revealed in our transmission eigenstates analysis. Regardless of the location, oxygen vacancies result in enhanced current in the system, whereas Zn vacancy defects reduce the charge transport across the junction. The current rectification becomes less pronounced in the presence of both types of vacancy defects. Our findings can be of practical importance for developing metal-insulator-metal diodes.

scholarly journals Effect of chemical modification on electronic transport properties of carbyne

2021 ◽  
Author(s):  
G. R. Berdiyorov ◽  
U. Khalilov ◽  
H. Hamoudi ◽  
Erik C. Neyts
Keyword(s):  
Transport Properties ◽  
Electronic Transport ◽  
Density Functional ◽  
Structural Changes ◽  
Carbon Chain ◽  
Functional Formalism ◽  
Functional Theory ◽  
Carbon Allotrope ◽  
Electronic Transport Properties ◽  
Interface Structures

AbstractUsing density functional theory in combination with the Green’s functional formalism, we study the effect of surface functionalization on the electronic transport properties of 1D carbon allotrope—carbyne. We found that both hydrogenation and fluorination result in structural changes and semiconducting to metallic transition. Consequently, the current in the functionalization systems increases significantly due to strong delocalization of electronic states along the carbon chain. We also study the electronic transport in partially hydrogenated carbyne and interface structures consisting of pristine and functionalized carbyne. In the latter case, current rectification is obtained in the system with rectification ratio up to 50%. These findings can be useful for developing carbyne-based structures with tunable electronic transport properties.

Magnetic Properties of Embedded Rh Clusters in Ni Matrix

1995 ◽  
Vol 384 ◽  
Author(s):  
Zhi-Qiang Li ◽  
Yuichi Hashi ◽  
Jing-Zhi Yu ◽  
Kaoru Ohno ◽  
Yoshiyuki Kawazoe
Keyword(s):  
Magnetic Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Magnetic Moments ◽  
Functional Formalism ◽  
Rhodium Clusters ◽  
Spin Polarized ◽  
Local Density Functional

ABSTRACTThe electronic structure and magnetic properties of rhodium clusters with sizes of 1 - 43 atoms embedded in the nickel host are studied by the first-principles spin-polarized calculations within the local density functional formalism. Single Rh atom in Ni matrix is found to have magnetic moment of 0.45μB. Rh13 and Rhl 9 clusters in Ni matrix have lower magnetic moments compared with the free ones. The most interesting finding is tha.t Rh43 cluster, which is bulk-like nonmagnetic in vacuum, becomes ferromagnetic when embedded in the nickel host.

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