Studies in molecular dynamics. XIII. Singlet and pair distribution functions for hard‐disk and hard‐sphere solids

1974 ◽  
Vol 60 (4) ◽  
pp. 1254-1267 ◽  
Author(s):  
David A. Young ◽  
Berni J. Alder
2010 ◽  
Vol 82 (10) ◽  
pp. 1943-1955 ◽  
Author(s):  
Maksym Druchok ◽  
Vojko Vlachy

An explicit water molecular dynamics (MD) simulation is presented of a solution modeling aliphatic 6,6-ionene oligocations mixed with low-molecular-weight electrolytes. In all cases, the co-ions were sodium cations and the counterions were fluoride, chloride, bromide, or iodide anions. The simple point charge/extended (SPC/E) model was used to describe water. The results of the simulation at T = 278 K (the data for 298 K were obtained earlier) and T = 318 K are presented in the form of pair distributions between various atoms and/or between ions in the system. We were interested in how temperature variation modifies the ion-specific effects, revealed by the various pair distribution functions (PDFs). The results were compared with previous calculations for the less hydrophobic 3,3-ionene solutions. Simulations of 6,6-ionene solutions containing mixtures of fluoride and iodide counter-ions at T = 298 K were also presented.


2010 ◽  
Vol 72 ◽  
pp. 337-342
Author(s):  
Masakazu Yarimitsu ◽  
Masaru Aniya

The pressure dependence of the diffusion coefficient in the superionic α- and β-phases of Ag3SI has been studied by using the method of molecular dynamics. It is shown that in the high temperature α-phase, the Ag diffusion coefficient decreases with pressure. On the hand, in the intermediate temperature β-phase, the Ag diffusion coefficient exhibits a maximum at around 2.8 GPa. The structural origin of this behavior is discussed through the pressure dependence of the pair distribution functions.


2014 ◽  
Vol 1035 ◽  
pp. 502-507
Author(s):  
Li An Chen

The structure and properties of the GexAsxS100-2x have been studied by ab initio molecular dynamics simulation. By calculating the pair distribution functions, bond angle distribution functions, we analyze the structure and properties of the alloys. Calculations show that Ge and As are all well combined with S atoms. When x is smaller than 25.0 the binding increases with x , when x is larger than 25.0 the binding decreases with increasing x . The intervention of As atom does not affect the GeS2 formation in Ge40As40S80


2021 ◽  
Vol 24 (3) ◽  
pp. 33605
Author(s):  
M. F. Holovko ◽  
M. Ya. Korvatska

Enskog theory is extended for the description of the self-diffusion coefficient of patchy colloidal fluid in disordered porous media. The theory includes the contact values of fluid-fluid and fluid-matrix pair distribution functions that are modified to include the dependence from the so-called probe particle porosity, φ, in order to correctly describe the effects of trapping the fluid particles by a matrix. The proposed expressions for the modified contact values of fluid-fluid and fluid-matrix pair distribution functions include three terms. Namely, a hard sphere contribution obtained by us in the previous work [Holovko M. F., Korvatska M. Ya., Condens. Matter Phys., 2020, 23, 23605], the depletion contribution connected with the cluster-cluster and cluster-matrix repulsion and the intramolecular correlation inside the cluster. It is shown that the last term leads to a remarkable decrease of the self-diffusion coefficient at a low fluid density. With a decreasing matrix porosity, this effect becomes weaker. For intermediate fluid densities, the depletion contribution leads to an increase of the self-diffusion coefficient in comparison with the hard sphere fluid. For a sufficiently dense fluid, the self-diffusion coefficient strongly decreases due to a hard sphere effect. The influence of the cluster size and the type of clusters as well as of the parameters of porous media is investigated and discussed in detail.


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