Structure and forces in liquid metals and alloys

1987 ◽  
Vol 65 (3) ◽  
pp. 219-240 ◽  
Author(s):  
N. H. March
Keyword(s):  
Structure Factor ◽  
Alkali Metals ◽  
Surface Segregation ◽  
Liquid Metals ◽  
Pair Potential ◽  
Liquid Structure ◽  
Cooperative Effects ◽  
Inversion Procedure ◽  
Chain Approximation ◽  
Three Body

The so-called force equation relating the pair function g(r), the three-body correlation function, and the assumed pair potential [Formula: see text] is first discussed from the standpoint of extracting force fields from diffraction measurements of the structure factor of liquid metals. Recent progress has been possible in this area by making use of the modified hypernetted-chain approximation, including the bridge function.A discussion is then given that relates the bridge function to vacancy-formation energy in hot close-packed metals, and also to the structure factor of the liquid. The possible role of cooperative effects in liquid metals on the inversion procedure is considered, as is the relation between three-body direct and total correlation functions.Pressing further the relation between liquid structure just above the melting point and the hot solid, advances in the theory of freezing are considered. The so-called Verlet rule on the height of the principal peak of the structure factor at melting is considered in relation to Lindemann's Law.After a brief discussion of the relation between structure and forces in liquid-metal alloys, the theory of inhomogeneous systems used to discuss freezing is applied to liquid surfaces, and in particular to surface segregation. The final topic treated is that of the critical constants of the fluid alkali metals, where it is argued that Coulomb forces are of decisive importance.

Relationship between Pair Potentials and Liquid Structure

1973 ◽  
Vol 51 (17) ◽  
pp. 1831-1839 ◽  
Author(s):  
L. E. Ballentine ◽  
J. C. Jones
Keyword(s):  
Structure Factor ◽  
Liquid Metals ◽  
Pair Potential ◽  
Liquid Structure ◽  
Main Peak ◽  
Repulsive Core ◽  
Pair Potentials ◽  
Eigenvector Analysis ◽  
Hypernetted Chain ◽  
Generalized Eigenvector

The Percus–Yevick and hypernetted chain theories are used to investigate the sensitivity of the pair potential [Formula: see text] to errors in the measured structure factor S(K) for several liquid metals and nonmetals. The linear relation between small errors, [Formula: see text], is studied by means of a generalized eigenvector analysis. Only those combinations of errors in S(K) which correspond to large eigenvalues lead to significant uncertainties in [Formula: see text]. The general form of the dominant eigenvectors was found to be the same for all liquids studied, except near the critical point. With this same exception, the following conclusions hold: Errors in S(K) for small K have by far the greatest effect on [Formula: see text]; the depth of the attractive portion of [Formula: see text] is most sensitive to errors in S(K); the repulsive core of [Formula: see text] is insensitive to errors in S(K); and the height of the main peak of S(K) has very little effect on [Formula: see text].

scholarly journals Self Diffusion in Liquid Metals

1975 ◽  
Vol 30 (5) ◽  
pp. 619-622
Author(s):  
R. V. Gopala Rao ◽  
A. K. Murthy
Keyword(s):  
Liquid Metals ◽  
Soft Part ◽  
Pair Potential ◽  
Spherical Model ◽  
Liquid Structure ◽  
Self Diffusion ◽  
Mean Spherical Model ◽  
The Mean ◽  
Square Well ◽  
Theory And Experiment

AbstractSelf-diffusion coefficients of liquid metals have been calculated according to the linear trajectory prescription. The soft part of the pair potential is being represented by a square well potential. The theoretical liquid structure factor, S(q), calculated under the mean spherical model (MSM) approximation, has been employed in the present calculations. The agreement between theory and experiment is encouraging and shows that the representation of the attractive forces by the square well potential is quite satisfactory for liquid metals.

Effect of changes in pair potential on the dynamical structure factor of molecular crystals

1980 ◽  
Vol 40 (6) ◽  
pp. 1517-1521 ◽  
Author(s):  
C.S. Murthy ◽  
K. Singer ◽  
M.L. Klein ◽  
I.R. McDonald
Keyword(s):  
Structure Factor ◽  
Molecular Crystals ◽  
Pair Potential ◽  
Dynamical Structure ◽  
Dynamical Structure Factor

scholarly journals Structure and Dynamics of Zr4+ in Aqueous Solution: An Ab Initio QM/MM Molecular Dynamics Study

2015 ◽  
Vol 15 (2) ◽  
pp. 155-162 ◽  
Author(s):  
Suwardi Suwardi ◽  
Harno Dwi Pranowo ◽  
Ria Armunanto
Keyword(s):  
Molecular Dynamics ◽  
Aqueous Solution ◽  
Distribution Function ◽  
Pair Potential ◽  
Structural Data ◽  
Angular Distribution Function ◽  
Dilute Aqueous Solution ◽  
Dynamical Properties ◽  
Experimental Values ◽  
Three Body

A QM/MM molecular dynamics (MD) simulation has been carried out using three-body corrected pair potential to investigate the structural and dynamical properties of Zr4+ in dilute aqueous solution. Structural data in the form of radial distribution function, coordination number distribution, and angular distribution function were obtained. The results indicate eight water molecules coordinate to zirconium ion and have two angles of O-Zr4+-O, i.e. 72.0° and 140.0° with a Zr4+-O distance of 2.34 Å. According to these results, the hydration structure of Zr4+ ion in water was more or less well-defined square antiprismatic geometry. The dynamical properties have been characterized by the ligand’s mean residence time (MRT) and Zr4+-O stretching frequencies. The inclusion of the three-body correction was important for the description of the hydrated Zr4+ ion, and the results indicated in good agreement with experimental values.

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