Theoretical Estimation of Temperature-Dependent Surface Tension of Liquid Antimony, Boron, and Sulfur
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e of the surface tension and its temperature dependence is paramount for various fundamental studies in atomic dynamics and surface physics. These properties are also needed when designing new highperformance alloys because the properties of an end member (e.g., binary, ternary systems, etc.) are required to estimate those of the final alloy. The limited knowledge on liquid boron and antimony has led us to study their thermophysical properties, mainly surface tension as a function of temperature. Also, considerable difference was present in the values of the surface tension of viscous sulfur because of the extremely high viscosity of liquid sulfur forming various chain length of polysulfur. Therefore, it was considered to be fundamentally necessary to determine theoretically the surface tension of viscous sulfur as a function of temperature. This paper is an extension to our previous work[11] that describes, in particular, the theoretical calculation of the temperature-dependence surface tension of antimony, boron and sulfur in a wide range temperature, and of the melting point surface tension of arsenic, selenium, tellurium, polonium, carbon (graphite), phosphorous (white), fluorine, chlorine, bromine, iodine, argon, and xenon. A comparison between the calculated and the existing experimental data is presented. The surface tension of liquid metals and non-metals has been found to be very susceptible to environmental contaminations. Experimental difficulties have limited investigation and most workers have been content with high temperature surface tension measurements at a single temperature close to the melting point. Although early methods of measurement of surface tension are sufficiently precise, there is still uncertainty regarding its absolute values. Computer simulations with Monte Carlo or molecular dynamics methods are considered to be one of the reliable methods with which surface tension can be calculated either using the mechanical expression for the surface stress or from the viewpoint of the surface energy. Unfortunately, the former approach suffers from rather high fluctuation and statistical uncertainty, whereas the latter introduces additional complexity into the performance. Thus, the demand of developing reliable prediction methods has never declined. Semiempirical predictions based on the correlation between the surface and bulk thermodynamic properties are always possible. The theoretical consideration, in our work, is based on classic statistical thermodynamics formulation of Eyring and coworkers.[12–14] Our recent published equation[11] was used before to calculate, theoretically, the surface tension of pure liquid gallium metal. The true form of this equation is given as follows: 2 ES 3 3 1 VS ð1 3fÞ þ ln ð1 þ fÞ kT c¼u 2 4 V RT
FATHI AQRA, Associate Professor and AHMED AYYAD, Assistant Professor, are with the Department of Chemistry, Faculty of Science and Technology, Hebron University, P.O. BOX 40, Hebron, West Bank, Palestine. Contact e-mail: [email protected] Manuscript submitted
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