Significant Structure Theory Research Articles

Vapor Pressure Isotope Effect near the Triple Point

The large discontinuity of the vapor pressure isotope effect (VPIE) observed near the triple point is discussed with the application of Bigeleisen's theory of equilibrium isotope effects in condensed phases to Eyring's significant structure theory of liquids. The partition function ratios are calculated for monatomic, diatomic, and polyatomic systems, and they are in good agreement with the experimental values. The simple molar volume change (Vs/Vl) is found to be adequate to explain the change in the vapor pressure ratios of 36Ar/40Ar, 20Ne/22Ne, 12C16O/13C16O, 12C16O/12C18O, and 12CH4/13CH4 systems, especially near the melting region. When the structural change at the melting point of ice is also taken into account, the VPIE is satisfactorily explained in the H2O/D2O system. The ``crossover'' phenomenon observed in systems like the isotopic methanes can be explained when the difference in the rotational contribution to the ratio of the reduced partition function ratios between the liquid and solid states is also taken into account. For isotopic hydrogen with large quantum effects, the isotope effect on the molar volume ratio must be included.

The Equilibrium and Transport Properties of Liquid Sulphur Dioxide from Significant Structure Theory

The Equilibrium and Transport Properties of Liquid Sulphur Dioxide from Significant Structure Theory

Utilization of the significant structure concepts in the study of the adsorption process from a solution

The significant structures theory of the liquid state is used to find a model of the adsorption process from a solution. This model leads to an expression of the adsorption rate. From this an adsorption isotherm and an interfacial equation of state are deduced. The boundary cases are studied.

Self-diffusion Measurements in Pure Liquids using Spin Echoes

Measurements of the coefficient of self-diffusion D have been carried out in oxygen-free samples of CH2Cl2, CH2Br2, and CH2I2 using spin echoes. The results show that the plots of In D vs. 1000/T are linear. The coefficients of self-diffusion decrease with increase in molecular weight and the activation energies of self-diffusion increase with increase in molecular weight. The results appear to be in agreement with the significant structure theory developed by Eyring and Ree.

Theory of hydrophobic bonding. I. Solubility of hydrocarbons in water, within the context of the significant structure theory of liquids

Theory of hydrophobic bonding. I. Solubility of hydrocarbons in water, within the context of the significant structure theory of liquids

The Thermodynamics of Liquid CD 4, HCN, C 2 N 2 and POCl 3 from Significant Structure Theory

The Thermodynamics of Liquid <i>CD</i> ₄, <i>HCN</i>, <i>C</i> ₂ <i>N</i> ₂ and <i>POCl</i> ₃ from Significant Structure Theory

The Thermodynamics of Liquid Iodine Monochloride and Arsenic Trifluoride and Significant Structure Theory

The Thermodynamics of Liquid Iodine Monochloride and Arsenic Trifluoride and Significant Structure Theory

Vapor Pressures of 36Ar and 40Ar. Intermolecular Forces in Solid and Liquid Argon

The vapor pressures of 36Ar and 40Ar have been measured in the temperature range 62–102°K. Measurements in the liquid agree quantitatively with the previous measurements of Clusius et al. which cover the limited range 84–88°K. A significant difference is found between our equilibrium measurements, which have a precision of 0.5% in the logarithm of the vapor pressure ratio, and dynamic measurements of the isotope fractionation in solid–vapor systems. The reduced partition functions of the solid and liquid are calculated from the observed vapor pressure ratios. The reduced partition ratio of the solid can be represented by the equation T2ln(fs / fg) = 63.39 ± 0.34 − (0.124 ± 0.005)T − (95 / 63)(63.4 − 0.124T)2 / T2. The experimental values of ln(fs / fg) are in good agreement with calculations from the improved self-consistent phonon theory of an anharmonic lattice with a 13–6 potential. Since the quantum effect is small, 〈∇2U〉 is obtained directly from the reduced partition functions. In the liquid range the experimental results agree quantitatively with previous estimates based on 12–6 potential, with calculations from molecular dynamics and with the Rowlinson correlation function. It is shown that the reduced 〈∇2U*〉 is the same for neon and argon both in the liquid and solid. The change in 〈∇2U〉 on melting is discussed in terms of the change of the number of nearest neighbors on melting and the “significant structure theory of liquids.”

The Thermodynamics of Liquid Hydrogen Sulphide and Carbon Monoxide and Significant Structure Theory

The Thermodynamics of Liquid Hydrogen Sulphide and Carbon Monoxide and Significant Structure Theory

Modification of the Significant Structure Theory of Liquids for Argon at High Pressures and Temperatures

The significant structure theory of liquids is applied to the shock and isothermal compression of argon. Three models and two types of intermolecular potential are considered. In Model 1, an Einstein oscillator model is used in the solid partition function. In Model 2, a Lennard-Jones and Devonshire cell model is used in the solid partition function. In Model 3, a cell model is used for the entire partition function (this version is independent of the significant structure theory). For the intermolecular potential, exp-6 and 12–6 are adopted separately with numerical parameters obtained from second virial coefficient and high-density shock wave experiments. The Einstein characteristic temperature and sublimation energy at absolute zero are calculated from the potential energy function based on the cell model. The experimental solidus is introduced for the molar volume of the solid. All the calculations are performed in a computer program without which analytical calculations are cumbersome or impossible. It is found that Model 1 with exp-6 potential provides the best fit to measurements. Calculated Hugoniot and isotherms agree well with experimental results.

The significant structure theory on the sound velocity and internal pressure of liquids

The validity of the model for the significant structure theory is tested by application of the theory to the sound velocity and internal pressure of liquids. The calculated results are in very good agreement with experimental values.

Theoretical Calculation of the Pressure Dependence of Liquid Hydrocarbon Viscosities

The extension of the significant structure theory of viscosity to the calculation of the viscosities of some selected liquid hydrocarbons such as n-C12, n-C15, and n-C18, etc., has been made. In this derivation, the explicit functional expressions of the molar solidlike volume Vs and the intermolecular potential φ(a) were introduced. The agreement between theory and experiment over a wide temperature (35–135°C) and pressure range (1–3600 bars) is quite satisfactory. The advantage of this treatment is that thermodynamic as well as transport properties are calculated from this same model of the liquid state.

Significant Structure Theory Applied to Surface Tension of Binary Liquid Mixtures

The surface tension of binary liquid mixtures, argon–nitrogen, oxygen–nitrogen, and oxygen–argon at 83.85°K were calculated by applying the significant-structure theory of liquids. In this paper, we calculate the contribution of successive layers to the surface tension. The calculations show that the top three layers of liquid mixture contribute to the surface tension. The curves obtained are in excellent agreement with experiment.

Significant-Structure Theory of Dynamic Liquid Properties

An acceptable model of the liquid state should lead to a quantitative theory of thermodynamic and transport properties. For simple substances such as argon, significant structure theory provides such a model without adjustable parameters. For more complicated molecules, a knowledge of certain properties allows one to calculate the remaining properties. A significant structure theory model which suffices to calculate the thermodynamic properties of liquids fixes transport properties aside from the numerical value of the transmission coefficient of reaction rate theory. The present status of the theory and of calculations of the following properties will be discussed: (a) ordinary viscosity, (b) bulk viscosity, (c) diffusion coefficients, (d) thermal conductivity, and (e) dielectric relaxation.

Free volume and significant structure theory applied to the viscosity of supercooled water

The viscosity of supercooled water has been computed on the basis of free volume and significant structure theories. Excellent agreement has been found between the calculated and experimental results, which confirms the idea of Barlow, Lamb, and Matheson (1966). An excellent correlation has been shown between the free volume and the volume of unbonded liquid at 0 and 10 °C, better than that shown by Miller (1963).

Significant structures theory of the surface tension of polyethylene

Significant structures theory of the surface tension of polyethylene

Application of significant structure theory to the correlation of thermodynamic properties of carbon dioxide, carbonyl sulfide, and carbon disulfide in terms of the respective molecular parameters

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTApplication of significant structure theory to the correlation of thermodynamic properties of carbon dioxide, carbonyl sulfide, and carbon disulfide in terms of the respective molecular parametersMelvin E. Zandler, James A. Watson Jr., and Henry EyringCite this: J. Phys. Chem. 1968, 72, 8, 2730–2737Publication Date (Print):August 1, 1968Publication History Published online1 May 2002Published inissue 1 August 1968https://doi.org/10.1021/j100854a007RIGHTS & PERMISSIONSArticle Views45Altmetric-Citations17LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (787 KB) Get e-Alerts

Anomalous Melting Transition in the Significant Structure Model of Liquids

The significant structure theory of Eyring et al. has been used to predict the melting curve of argon at high pressure. Anomalous results were obtained, which indicate that the model may not be suitable to describe the phenomenon of melting. Possible reasons for these results are discussed.

SILICA GLASS: A BENT-BOND MODEL

from distorted hexagonal rings. These grains are joined together by rings other than 6-membered, probably mostly 7- and 5-membered, but 8- and 4-membered rings would not seem impossible. In the example shown in Figure 1, the tetrahedra represent Si atoms and the bent links 0 atoms. The model was built mostly from 6membered rings, but contains several 5- and 7-membered rings. When the Si-O bonds in the cristobalite lattice bend and rotate to the extents indicated, long-range order ceases and the structure melts. Relatively few bonds need to be broken, but some are. These are rejoined in a largely random way, and require the migration of some SiO2 molecules in order to preserve electrical neutrality. On the basis of Eyring's significant structure theory of liquids,4 the holes in the liquid which reflect the structure of the solid are those extra positions in the neighborhood of each Si and 0 atom about their equilibrium positions in the solid which can be filled by the atoms when the bonds are bent and rotated to form the liquid. These can be considered to provide solidlike degrees of freedom and are to be associated with 6-membered rings. The gaslike degrees of freedom are used by the migrating SiO2 molecules which result from formation of 5-membered, 7-membered, and possibly other kinds, but not 6-membered rings. The bent and rotated

Application of significant structures theory to amorphous polyethylene

AbstractThe thermodynamic properties of amorphous polyethylene are calculated from a model based on the method of significant structures. The motion of a molecule as a whole is described by the motion of segments, each segment moving independently of all others. It is assumed that on melting, holes appear in the solid lattice and the segments can move into these vacancies, obtaining some gaslike degrees of freedom. The complete frequency distribution for polyethylene is used for the solidlike degrees of freedom, while a corrected classical partition function is used for the gaslike degrees of freedom. The calculated thermodynamic properties are in reasonable agreement with experimentally determined values, assuming each gaslike segment to consist of 20 CH2 groups.