Structure of chemically reacting particles near a hard wall from integral equations and computer simulations

1996 ◽  
Vol 74 (1-2) ◽  
pp. 65-76 ◽  
Author(s):  
A. Trokhymchuk ◽  
D. Henderson ◽  
S. Sokołowski
Keyword(s):  
Monte Carlo ◽  
Computer Simulations ◽  
Hard Spheres ◽  
Total Density ◽  
Hard Wall ◽  
Monte Carlo Data ◽  
Density Profiles ◽  
Interparticle Potential ◽  
Theoretical Predictions ◽  
Chemically Reacting

We performed Monte-Carlo computer simulations of a fluid of chemically reacting, or overlapping, hard spheres near a hard wall. The model of the interparticle potential is that introduced by Cummings and Stell. This investigation is directed to the determination of the structure of the fluid at the wall, and the orientation of the dimers in particular. In addition, we applied the singlet Percus–Yevick, hypernetted chain and Born–Green–Yvon equations to calculate the total density profiles of the particles. A comparison with the Monte-Carlo data indicates that the singlet Percus–Yevick theory is superior and leads to results that are in reasonable agreement with simulations for all the parameters investigated. We also calculated the average numbers of dimers formed in the bulk part of the system and the results are compared with different theoretical predictions.

scholarly journals Impact of background effects on the inclusive Vcb determination

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Thomas Mannel ◽  
Muslem Rahimi ◽  
K. Keri Vos
Keyword(s):  
Monte Carlo ◽  
Heavy Quark ◽  
High Precision ◽  
Monte Carlo Methods ◽  
Monte Carlo Data ◽  
Theoretical Predictions ◽  
Experimental Side ◽  
Belle Ii

Abstract The determination of the CKM element Vcb from inclusive semileptonic b → cℓ$$ \overline{\nu} $$ ν ¯ decays has reached a high precision thanks to a combination of theoretical and experimental efforts. Aiming towards even higher precision, we discuss two processes that contaminate the inclusive Vcb determination; the b → u background and the contribution of the tauonic mode: b → c(τ → μν$$ \overline{\nu} $$ ν ¯ )$$ \overline{\nu} $$ ν ¯ . Both of these contributions are dealt with at the experimental side, using Monte-Carlo methods and momentum cuts. However, these contributions can be calculated with high precision within the Heavy-Quark Expansion. In this note, we calculate the theoretical predictions for these two processes. We compare our b → u results qualitatively with generator-level Monte-Carlo data used at Belle and Belle II. Finally, we suggest to change the strategy for the extraction of Vcb by comparing the data on B → Xℓ directly with the theoretical expressions, to which our paper facilitates.

Contact Value Formulae for the Density Profiles of the Electric Double Layer

2008 ◽  
Vol 73 (4) ◽  
pp. 558-574 ◽  
Author(s):  
Douglas J. Henderson ◽  
Lutful B. Bhuiyan
Keyword(s):  
Computer Simulations ◽  
Density Profile ◽  
Physical Interpretation ◽  
Electric Double Layer ◽  
Reasonable Agreement ◽  
Hard Wall ◽  
Density Profiles ◽  
Sum Rule ◽  
Recent Computer ◽  
Local Expression

An exact sum rule, due to Henderson, Blum, and Lebowitz, for the contact value of the density profile of ions in a primitive model electrolyte next to a planar, nonpolarizable charged hard wall, has been known for some years. This result has a pleasing physical interpretation and is local. It has been useful in assessing the accuracy of theoretical approximations. However, a sum rule for the contact value of the charge profile for the same system has, until recently, not been known. A few years ago, Boda and Henderson proposed what they thought might be a useful, but approximate, local expression for the contact value of the charge profile at a weakly charged electrode. Very recent computer simulations indicate that this expression may well be exact at low electrode charge. Recently, Holovko, Badiali, and di Caprio have obtained a more general, but nonlocal, sum rule for the contact value of the charge profile that is valid for all electrode charge. In this paper, we develop an alternative, nonlocal, but nonrigorous expression for this quantity. Both the expression of Holovko et al. and our new expression are examined by means of computer simulations. The Holovko et al. expression is exact and, within numerical uncertainties, seems supported by our simulations. Although admittedly nonrigorous, our simpler expression is in seemingly reasonable agreement with simulation and thus appears to be useful. The relation between the two expressions has not been established.

Monte Carlo and Perturbation Calculations for a Triangular Well Fluid

1974 ◽  
Vol 52 (1) ◽  
pp. 80-88 ◽  
Author(s):  
Damon N. Card ◽  
John Walkley
Keyword(s):  
Monte Carlo ◽  
Hard Spheres ◽  
Low Density ◽  
Monte Carlo Data ◽  
Density Region ◽  
Wide Range ◽  
Model Fluid ◽  
High Density Region ◽  
Superposition Approximation ◽  
Triangular Well Potential

Monte Carlo data have been generated for a simple model fluid consisting of hard spheres with an attractive triangular well potential. The ranges spanned by the temperature and density are as follows. [Formula: see text] and [Formula: see text]. The machine data have been compared to the modern perturbation theories of (i) Barker, Henderson, and Smith and (ii) Weeks, Chandler, and Andersen. Comparison with the machine data shows that the latter theory is successful in the high density region only, but over a wide range of temperature. The Barker–Henderson approach is best in the low density region but the use of the superposition approximation limits the utility of this theory at high densities.

THEORETICAL INVESTIGATION OF ASYMMETRIC SIMPLE EXCLUSION PROCESSES WITH OFF-RAMP ON THE BOUNDARIES

2012 ◽  
Vol 26 (24) ◽  
pp. 1250155 ◽  
Author(s):  
SONG XIAO ◽  
SHUYING WU ◽  
LIQIONG TANG ◽  
DONGSHENG ZHENG ◽  
JING SHANG
Keyword(s):  
Field Theory ◽  
Monte Carlo ◽  
Computer Simulations ◽  
Mean Field Theory ◽  
Mean Field ◽  
Exclusion Processes ◽  
Density Profiles ◽  
Asymmetric Simple Exclusion ◽  
Simple Exclusion ◽  
Good Agreement

In this letter, asymmetric simple exclusion processes with off-ramp on the boundaries have been studied by asymmetric simple exclusion processes (ASEPs). In this model, particles can only detach from a single off-ramp on the boundaries of the system. The phase diagrams and density profiles are calculated by approximate mean field theory and have shown good agreement with the extensive Monte Carlo computer simulations.

scholarly journals Confined Quantum Hard Spheres

Entropy ◽  
2021 ◽  
Vol 23 (6) ◽  
pp. 775
Author(s):  
Sergio Contreras ◽  
Alejandro Gil-Villegas
Keyword(s):  
Computer Simulation ◽  
Monte Carlo ◽  
Computer Simulations ◽  
Hard Spheres ◽  
Quantum Systems ◽  
Confined Space ◽  
Free Energies ◽  
Classical Systems ◽  
Accessible Volume ◽  
Theoretical Results

We present computer simulation and theoretical results for a system of N Quantum Hard Spheres (QHS) particles of diameter σ and mass m at temperature T, confined between parallel hard walls separated by a distance Hσ, within the range 1≤H≤∞. Semiclassical Monte Carlo computer simulations were performed adapted to a confined space, considering effects in terms of the density of particles ρ*=N/V, where V is the accessible volume, the inverse length H−1 and the de Broglie’s thermal wavelength λB=h/2πmkT, where k and h are the Boltzmann’s and Planck’s constants, respectively. For the case of extreme and maximum confinement, 0.5<H−1<1 and H−1=1, respectively, analytical results can be given based on an extension for quantum systems of the Helmholtz free energies for the corresponding classical systems.

scholarly journals Understanding the interfacial behavior in isopycnic Lennard-Jones mixtures by computer simulations

2016 ◽  
Vol 18 (2) ◽  
pp. 1114-1124 ◽  
Author(s):  
José Matías Garrido ◽  
Manuel M. Piñeiro ◽  
Andrés Mejía ◽  
Felipe J. Blas
Keyword(s):  
Computer Simulations ◽  
Total Density ◽  
Interfacial Behavior ◽  
Density Profiles ◽  
Lennard Jones

Singular structures of total density profiles under molar isopycnicity conditions.

Thermodynamic properties of pure hard sphere, spherocylinder and dumbell fluids

1979 ◽  
Vol 44 (12) ◽  
pp. 3555-3565 ◽  
Author(s):  
Ivo Nezbeda ◽  
Jan Pavlíček ◽  
Stanislav Labík
Keyword(s):  
Monte Carlo ◽  
Equation Of State ◽  
Thermodynamic Properties ◽  
Hard Sphere ◽  
Arbitrary Shape ◽  
Hard Spheres ◽  
Monte Carlo Data ◽  
Universal Equation

A universal equation of state for the fluid of hard bodies of an arbitrary shape is proposed. New Monte Carlo data of the hard sphere system are published and the existing pseudoexperimental data for hard spheres, spherocylindres and dumbells are critically reviewed.

Density profiles for a dimerizing hard sphere fluid near an associatively adsorbing hard wall: a Monte Carlo study

1996 ◽  
Vol 88 (6) ◽  
pp. 1491-1502 ◽  
Author(s):  
ANDRIJ TROKHYMCHUK ◽  
OREST PIZIO ◽  
DOUGLAS HENDERSON ◽  
STEFAN SOKOLOWSKI
Keyword(s):  
Monte Carlo ◽  
Hard Sphere ◽  
Monte Carlo Study ◽  
Hard Wall ◽  
Density Profiles ◽  
Hard Sphere Fluid
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