Structure Factor Of Liquid Metals Research Articles

A semi-analytical solution of the mean spherical approximation: Application to calculation of structure factors of liquid metals in the square-well model

A semi-analytical solution of the mean spherical approximation: Application to calculation of structure factors of liquid metals in the square-well model

Calculation of the structure factor of liquid metals

Applying the solution of the Percus-Yevick equation to a one component system and using a screened pseudopotential, a model is developed for calculating the structure factor of liquid metals at different temperatures and densities. The model was tested using both simple and non-simple liquid metals. The results obtained were in very good agreement with experimental values for all the metals used to test the model. The model can reproduce the peak positions in the structure factor of liquid metals within the limit of experimental errors. Also the study revealed that the peak positions in the structure factor of liquid metals occur when the screened potential is a minimum. Also, increase in temperature increases the magnitude of the structure factor but does not affect the peak positions. The model can be use to calculate the structure factor of liquid metals at different temperatures and densities. Keywords:One component, structure, factor, screened potential Nigerian Journal of Physics Vol. 18 (1) 2006: pp. 25-32

Low-angle structure factor behavior of expanded liquid metals

The investigation of the low-angle behavior of the ion-ion static structure factor for liquid metals is performed on the basis of pseudopotential theory and OCP models for degenerated electrons and classic ions. The important influence of the electron correlations for the low-angle structure is shown. Good agreement with the experimental data is obtained for liquid cesium in a wide range of temperatures.

Long‐Wavelength Limit of the Structure Factor of Liquid Metals from the Charged Hard‐Sphere Reference System

AbstractA detailed study of the long‐wavelength limit S(0) of the structure factor of alkali metals and some polyvalent metals at their freezing points using the charged hard‐sphere reference system is made. In order to investigate the role of refinements in the description of the electron‐ion interaction, use is made of both the Ashcroft empty‐core model (ECM) potential and a non‐local pseudopotential which incorporates high‐order perturbation corrections. The results obtained from the random‐phase approximation (RPA) are compared with those using the mean‐density approximation (MDA). Our calculations indicate that to obtain an accurate description of S(0) within the present framework, a good method of dealing with the electron‐ion pseudopotential is essential. It is also observed that the MDA correction in most cases does not lead to a remarkable improvement on those obtained from the RPA.

Computation of structure factors of liquid metals by use of the sticky-hard-sphere potential.

The structure factors of several liquid metals have been calculated through the Baxter solution of the Percus-Yevick equation for a sticky-hard-sphere potential. The computed structure factors are in excellent agreement with experiment, thus showing that the sticky-hard-sphere model, which has only two parameters, is quite good in explaining structural properties. From the calculated structure factors the corresponding radial distribution functions g(r) have been computed for different metals and, hence, the nearest-neighbor distance, the coordination number, and the Ashcroft effective number of electrons per metallic atom.

Temperature Dependence of the Static Structure Factor for Liquid Bi, Ga, Sb, and Sn

AbstractA simple approach is presented to calculate the temperature dependence of the static structure factor for non‐simple liquid metals, based on the hard sphere cluster model and considering the temperature dependence of the hard sphere diameters and atomic percentage of the second type of clusters. The structure factors of liquid metals are calculated for Bi (T = 300, 500, 550, 800, and 950 °C), Ga (T = 50, 200, 550, 800, and 1000 °C), Sb (T = 660 and 800 °C), and Sn (T = 250, 300, 700, 900, and 1100 °C). The calculated results are in good agreement with experiments.

Structure and forces in liquid metals and alloys

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.

Structure factor of liquid metals in one-component plasma system

We present the analytical expression to determine the static structure factorS(q) of liquid alkali metals based on the semi-analytic theory of Baus and Hansen. The calculations were motivated to point out the anomalies exhibited by one-component plasma system (ocp) in describing the structure factor. The numerical example of Na illustrates our results.ocp structure factor is also compared with those obtained by the hard sphere system.

A program for calculating the structure factors of liquid metals and binary liquid alloys

A program for calculating the structure factors of liquid metals and binary liquid alloys

Influence of pair potential oscillations on the structure factor of liquid metals

The pair potential of liquid metals shows damped oscillations at long range. Using a form for this pair potential, proposed by Cummings, we calculate the structure factor in the random phase approximation. We give a description of the behaviour to pair potential oscillations of the structure factor and some numerical results, for 12 liquid metals. The applicability of this model has been tested by calculating the long-wavelength limit.

The Structure Factors of Liquid Metals in Low Q Region

The low Q structure factors have been determined in the region down to Q = 0.08A-1 for liquid Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Al and In at several temperatures by x-ray diffraction with the transmission mode. The low- Q structure factor is a slowly increasing function of Q, and its profile is quite similar among the liquid metals presently investigated. The long wavelength limit value of S(Q) derived from the present experimental structural data agrees well with that calculated from the isothermal compressibility for seven metals near the melting point. A differ­ence larger than 10% was found in the cases of liquid Cs, Ca and Al.

Temperature dependence of the structure factor of liquid metals

AbstractAn expression for temperature dependent packing density is obtained and it is shown that this temperature dependent packing density can account the temperature dependence of structure factor, self‐diffusion coefficient, and shear viscosity with good accuracy. Other observations at higher temperatures also confirm this procedure.

On the use of the one-component-plasma model for the structure factors of liquid metals

It is demonstrated that the perturbative correction, appearing in the structure factor of the simple liquid metals in the one-component-plasma model, is important and may have to be calculated more rigorously than by the usual semi-non-local or local pseudopotential theory.

A program for calculating the structure factors of liquid metals and binary liquid alloys

A program for calculating the structure factors of liquid metals and binary liquid alloys

Calculation of the Structure Factor of Liquid Metals.

Calculation of the Structure Factor of Liquid Metals.

A Possible Closed Form Expression for the Static Structure Factor for Liquid Metals

A Possible Closed Form Expression for the Static Structure Factor for Liquid Metals

Calculation of the Structure Factor of Liquid Metals

Calculation of the Structure Factor of Liquid Metals

Temperature and density dependent Ashcroft-Lekner structure factor for liquid metals

Through Zwanzig's method to describe liquified noble gases, we have obtained a generalization of Ashcroft-Lekner structure factor for liquid metals. The structure factor parameters are now explicitly density and temperature dependent.

Entropies and structure factors of liquid metals

Recent theory, relating the thermodynamics for a real liquid to that of a hard sphere reference system suggests a correlation between the entropy and the structure factor. The extent to which this correlation exists in liquid metals is investigated by comparing, for each system and at various temperatures, the packing fractions deduced respectively from entropy and structure factor measurements. The quality of agreement is, overall, comparable with that obtained from previous comparisons of measured and hard sphere structure factors as functions of wave number. The standard ab initio method of calculating interatomic forces in simple metals uses pseudopotential theory. It is suggested that near the melting points entropies for all valencies, and specific heats for lower (<or=3) valencies, are adequately described by the usual pseudopotential techniques.

A Feasibility Study of Applying Neutron T-O-F Method for the Liquid Structure Analysis

A preliminary study of applying the time-of-flight neutron diffraction method for the determination of the structure factor of liquid metals has been examined. The diffraction pattern of liquid Sn at 260°C has been measured using a time-of-flight neutron diffractometer incorporated with a pulsed neutron source from an electron linear accelerator, and a fairly good agreement between the present results and those of North et al.1) has been obtained. It is concluded that the T-O-F method incorporated with a pulsed neutron source can yield reliable data for the liquid metal structure analysis which are as accurate as those obtained from a steady reactor.