The first coordination number for liquid metals

2004 ◽  
Vol 82 (4) ◽  
pp. 291-301 ◽  
Author(s):  
J R Cahoon
Keyword(s):  
Distribution Function ◽  
Radial Distribution Function ◽  
Coordination Number ◽  
Liquid Metals ◽  
Liquid Density ◽  
Isotropic Liquid ◽  
Coordination Numbers ◽  
Solid Structure ◽  
Atomic Diameter ◽  
Liquid Element

A simple and absolute method for the calculation of the first coordination number for any pure, isotropic liquid element is presented. The liquid density and the position for the first peak of the radial distribution function, assumed to be the atomic diameter, are the only parameters required. The coordination number for liquid metals that exhibit a BCC (body-centred cube) solid structure averages 7.4 while the first coordination number for liquid metals with a FCC (face-centred cube) or CPH (close-packed hexagonal) solid structure averages 7.1. Those liquid elements that have less closed-packed solid structures have a first coordination number less than 7.0. The calculation also correctly predicts the first coordination number for liquid Se to be 2.4, consistent with its chain-like structure. The calculated values for the liquid element coordination numbers are consistent with the decrease in density of a few percent that occurs upon melting and appear to be related to the Engel–Brewer valence of the solid, which suggests that the electron structure of the solid may be retained upon melting. The first coordination numbers for liquid Ge and Si were calculated to be 5.0 and 4.7, respectively, larger than the value of 4.0 for solid structures. The increase in coordination number upon melting accounts for the increase in density of Ge and Si that occurs upon melting.PACS No.: 61.20.Gy

Local Structure of MD Simulated Soda-Lime-Silicate Glass

1996 ◽  
Vol 455 ◽  
Author(s):  
Xianglong Yuan ◽  
Alastair N. Cormack
Keyword(s):  
Molecular Dynamics ◽  
Distribution Function ◽  
Radial Distribution Function ◽  
Coordination Number ◽  
Silicate Glass ◽  
Local Structure ◽  
Soda Lime ◽  
Composition Change ◽  
Soda Lime Silicate Glass ◽  
Cluster Phenomenon

ABSTRACTSimulation of soda-lime-silicate (sis) glass has been performed using molecular dynamics (MD). The local structure of each component is analyzed extensively in terms of total radial distribution function and coordination number and found to be insensitive to the composition change. Because of its big size, Na+/Ca2+ shows a behavior rather like O2− instead of Si4+. It is evident that the CN and local structure of Na+ with O2− are similar to those in crystalline a-Na2Si2O5. Finally, the Na+/Ca2+ cluster phenomenon is discussed.

scholarly journals Coordination number for random distribution of parallel fibres

2017 ◽  
Vol 38 (1) ◽  
pp. 3-26 ◽  
Author(s):  
Piotr Darnowski ◽  
Piotr Furmański ◽  
Roman Domanski
Keyword(s):  
Distribution Function ◽  
Coordination Number ◽  
Pair Distribution Function ◽  
Sequential Analysis ◽  
Random Distribution ◽  
Coordination Numbers ◽  
Random Sequential Addition ◽  
Wide Range ◽  
Parallel Fibres ◽  
Sequential Addition

AbstractThis paper presents the results of computer simulations carried out to determine coordination numbers for a system of parallel cylindrical fibres distributed at random in a circular matrix according to twodimensional pattern created by random sequential addition scheme. Two different methods to calculate coordination number were utilized and compared. The first method was based on integration of pair distribution function. The second method was the modified sequential analysis. The calculations following from ensemble average approach revealed that these two methods give very close results for the same neighbourhood area irrespective of the wide range of radii used for calculation.

scholarly journals Molecular Dynamics Study the Factors Effecting the Structure of MgSiO3 Bulk

2019 ◽  
Vol 8 (2) ◽  
pp. 10
Author(s):  
Dung Nguyen Trong ◽  
Huy Nguyen Quoc
Keyword(s):  
Molecular Dynamics ◽  
Distribution Function ◽  
Boundary Conditions ◽  
Radial Distribution Function ◽  
Coordination Number ◽  
Periodic Boundary ◽  
Periodic Boundary Conditions ◽  
Angle Distribution ◽  
Structural Units ◽  
Dynamics Method

This paper studies the effect of atomic numbers (N), N=2000atoms, 3000atoms, 4000atoms, 5000atoms, 6000atoms at temperature (T), T=300K; N=5000atoms at T=300K, 500K, 1000K, 1500K, 2000K, 2500K, 3000K, 3500K; N=5000atoms at T=300K, 2000K with pressure (P), P=0GPa, 20GPa, 40GPa, 60GPa, 80GPa, 100GPa on the structure of MgSiO3 bulk by Molecular Dynamics method (MD) with Born-Mayer potential (BM), periodic boundary conditions. The results were analyzed through the radial distribution function (RDF), coordination number, angle distribution, size (l), energy (E). The results showed that there are the effects of factors on the structure of MgSiO3 bulk. In addition, with the atomic number (N), temperature (T), different pressures (P) at temperature T=300K, 2000K there are the appearance and disappearance of links Si-Si, Si-O, O-O, Si-Mg, O-Mg, Mg-Mg and number of structural units SiO4, SiO5, SiO6, MgO3, MgO4, MgO5, MgO6, MgO7, MgO8, MgO9 , MgO10, MgO11, MgO12

scholarly journals Effects of Number of Atoms, Shell Thickness, and Temperature on the Structure of Fe Nanoparticles Amorphous by Molecular Dynamics Method

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Dung Nguyen Trong ◽  
Van Cao Long
Keyword(s):  
Molecular Dynamics ◽  
Distribution Function ◽  
Radial Distribution Function ◽  
Coordination Number ◽  
Radial Distribution ◽  
Shell Thickness ◽  
Structural Parameters ◽  
Peak Position ◽  
Glass Temperature ◽  
Structural Factors

This study aims to study the effect of several structural factors, such as number of atoms (N), shell thickness (d), and temperature (T), on the structure of amorphous iron nanoparticle (amorphous nano-Fe) by using the molecular dynamics (MD) method with Sutton–Chen (SC) dip interaction and free boundary conditions. The structural parameters of amorphous nano-Fe include their size (D), energy (E), radial distribution function (RDF), coordination number (CN), and coordination number density (CNd). The results show that the glass temperature ( T g ) and the first peak position (r) of radial distribution function (RDF) have the values of T g  = 900 K and r = 2.55 Å, respectively. Furthermore, the values of parameters D and E are always proportional to N−1/3 and N−1, respectively. Regarding the effect of number of atoms, shell thickness, and the temperature on the structure of amorphous nano-Fe, we found that the increase in atoms number leads to decrease in the RDF height and increase in the coordination number (CN). However, increasing temperature leads to decreasing the shell thickness of amorphous nano-Fe.

Simulation of Structure and Dynamics of Amorphous SiO2

1996 ◽  
Vol 446 ◽  
Author(s):  
Y. Kogure ◽  
M. Doyama
Keyword(s):  
Molecular Dynamics ◽  
Computer Simulation ◽  
Distribution Function ◽  
Radial Distribution Function ◽  
Radial Distribution ◽  
Amorphous Structure ◽  
Amorphous Sio2 ◽  
Coordination Numbers ◽  
Structure And Dynamics ◽  
External Stresses

AbstractA molecular dynamics computer simulation of amorphous SiO2 has been made to investigate the structure and dynamics. The effects of the external stresses on the amorphous structure were investigated through the radial distribution function, the distribution of Si‐O‐Si bond angles, and the distribution of coordination numbers.

The Influence of Hydrogen atoms on the Performance of Radial Distribution Function Based Descriptors in the Chemoinformatic Studies of HIV-1 Prote-ase Complexes with Inhibitors.

2020 ◽  
Vol 17 ◽  
Author(s):  
Jurica Novak ◽  
Maria A. Grishina ◽  
Vladimir A. Potemkin
Keyword(s):  
Distribution Function ◽  
Radial Distribution Function ◽  
Radial Distribution ◽  
Current Model ◽  
Direct Interaction ◽  
Hydroxyl Group ◽  
Linear Regression Method ◽  
Hydrogen Atoms ◽  
Protease Enzyme ◽  
Hiv 1

: In this letter the newly introduced approach based on the radial distribution function (RDF) weighted by the number of va-lence shell electrons is applied for a series of HIV-1 protease enzyme and its complexes with inhibitors to evaluate the influ-ence of hydrogen atoms on the performance of the model. The multiple linear regression method was used for the selection of the relevant descriptors. Two groups of residues having dominant contribution to the RDF descriptor are identified as relevant for the inhibition. In the first group are residues like Arg8, Asp25, Thr26, Gly27 and Asp29, which establish direct interaction with the inhibitor, while the second group consists of the amino acids at the interface of the two homodimer sub-units or with the solvent. The crucial motif pointed out by our approach as the most important for inhibition of the enzyme’s activity and present in all inhibitors is hydroxyl group that establish hydrogen bond with Asp25 side chain. Additionally, the comparison to the model without hydrogen showed that both models are of similar quality, but the downside of the current model is the need for the determination of residues’ protonation states.

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