On applicability of Gibbs thermodynamics to nanoparticles

Open Physics ◽  
2003 ◽  
Vol 1 (3) ◽  
Author(s):  
V. Samsonov ◽  
A. Bazulev ◽  
N. Sdobnyakov
Keyword(s):  
Surface Tension ◽  
Free Energy ◽  
Excess Free Energy ◽  
Particle Radius ◽  
Phase Method ◽  
Surface Phase ◽  
Effective Surface

AbstractThe problem of applicability of thermodynamics to small objects has been investigated. It is shown that the Gibbs surface phase method may be extended to nanoparticles if the effective surface tension (the specific excess free energy) is interpreted as a function of the particle radius.

scholarly journals Monte Carlo Calculations of Effective Surface Tension for Small Clusters

1996 ◽  
Vol 49 (2) ◽  
pp. 425 ◽  
Author(s):  
Barbara N Hale
Keyword(s):  
Surface Tension ◽  
Monte Carlo ◽  
Free Energy ◽  
Water Clusters ◽  
Bulk Liquid ◽  
Effective Surface ◽  
Pair Potentials ◽  
Excess Surface ◽  
Metropolis Monte Carlo ◽  
Small Clusters

In this study we have calculated configurational Helmholtz free energy differences between n and n – 1 molecule water clusters and nand n – 1 atom argon clusters using classical effective atom-atom pair potentials and the Bennett–Metropolis Monte Carlo technique. When plotted versus n–1/ 3 the slope of the free energy differences yields an effective surface tension, σ. It is found that these slopes display a universal (material independent) property related to the excess surface entropy / κ per molecule (or atom), Ω. For most materials (in the bulk liquid state) the latter quantity is about 2. The results indicate that clusters as small as n = 10 display bulk surface free energy properties. The temperature dependence of the effective surface tension for the model water clusters is also investigated and is consistent with a simple scaled form, σ / κTρ2/3liquid ≈ Ω(Tc /T – 1), where Tc = 647 K and Ω = 1�9.

On the size dependence of surface tension in the temperature range from melting point to critical point

Open Physics ◽  
2005 ◽  
Vol 3 (2) ◽  
Author(s):  
Nickolay Sdobnyakov ◽  
Vladimir Samsonov
Keyword(s):  
Surface Tension ◽  
Critical Point ◽  
Size Dependence ◽  
Excess Free Energy ◽  
Thermodynamic Perturbation Theory ◽  
Effective Surface ◽  
Temperature Range ◽  
Lennard Jones ◽  
Dividing Surface ◽  
First Time

AbstractThe problem of size dependence of surface tension was investigated in view of a more general problem of the applicability of Gibbs’ thermodynamics to nanosized objects. For the first time, the effective surface tension (coinciding with the specific excess free energy for an equimolecular dividing surface) was calculated within a wide temperature range, from the melting temperature to the critical point, using the thermodynamic perturbation theory. Calculations were carried out for Lennard-Jones and metallic nanosized droplets. It was found that the effective surface tension decreases both, with temperature and particle size.

Comparison of a Non Electrostatic Surface Complexation Model and Surface Phase Theories for Prediction of Future Sorption Properties.

2004 ◽  
Vol 824 ◽  
Author(s):  
Allan T. Emrén ◽  
Anna-Maria Jacobsson
Keyword(s):  
Aqueous Solution ◽  
Chemical Potential ◽  
Surface Complexation ◽  
Sorption Properties ◽  
Phase Method ◽  
Detailed Knowledge ◽  
Surface Phase ◽  
Surface Complexation Model ◽  
Advantages And Disadvantages ◽  
The One

AbstractIn performance assessments, sorption of radionuclides dissolved in groundwater is mostly handled by the use of fixed Kd values. It has been well known that this approach is unsatisfying. Only during the last few years, however, tools have become available that make it possible to predict the actual Kd value in an aqueous solution that differs from the one in which the sorption properties were measured.One such approach is surface complexation (SC) that gives a detailed knowledge of the sorption properties. In SC, one tries to find what kinds of sorbed species are available on the surface and the thermodynamics for their formation from species in the bulk aqueous solution. Recently, a different approach, surface phase method (SP), has been developed. In SP, a thin layer including the surface is treated as a separate phase. In the bulk aqueous solution, the surface phase is treated as a virtual component, and from the chemical potential of this component, the sorption properties can be found.In the paper, we compare advantages and disadvantages of the two kinds of models. We also investigate the differences in predicted sorption properties of a number of radionuclides (Co, Np, Th and U). Furthermore, we discuss under which circumstances, one approach or the other is preferable.

Characterization of Textured Aluminum Lines and Modelling of Stress Voiding

1994 ◽  
Vol 343 ◽  
Author(s):  
S.C. Wardle ◽  
B.L. Adams ◽  
C.S. Nichols ◽  
D.A. Smith
Keyword(s):  
Free Energy ◽  
Excess Free Energy ◽  
Mean Field ◽  
High Energy ◽  
Polycrystalline Structure ◽  
Field Approach ◽  
Bamboo Structure ◽  
Automated Technique ◽  
Theory And Modeling

ABSTRACTIt is well known from studies of individual interfaces that grain boundaries exhibit a spectrum of properties because their structure is misorientation dependent. Usually this variability is neglected and properties are modeled using a mean field approach. The limitations inherent in this approach can be overcome, in principle, using a combination of experimental techniques, theory and modeling. The bamboo structure of an interconnect is a particularly simple polycrystalline structure that can now be readily characterized experimentally and modeled in the computer. The grain misorientations in a [111] textured aluminum line have been measured using the new automated technique of orientational imaging microscopy. By relating boundary angle to diffusivity the expected stress voiding failure processes can be predicted through the link between misorientation angle, grain boundary excess free energy and diffusivity. Consequently it can be shown that the high energy boundaries are the favored failure sites thermodynamically and kinetically.

Higher Order Conditional Probabilities and Thermodynamics of Binary Molten Alloys

1997 ◽  
Vol 11 (02n03) ◽  
pp. 93-106 ◽  
Author(s):  
O. Akinlade
Keyword(s):  
Free Energy ◽  
Experimental Evidence ◽  
Cluster Model ◽  
Excess Free Energy ◽  
Higher Order ◽  
Thermodynamic Quantities ◽  
Equiatomic Composition ◽  
Conditional Probabilities ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing

The recently introduced four atom cluster model is used to obtain higher order conditional probabilities that describe the atomic correlations in some molten binary alloys. Although the excess free energy of mixing for all the systems studied are almost symmetrical about the equiatomic composition, most other thermodynamic quantities are not and thus, the study enables us to explain the subtle differences in their physical characteristics required to describe the mechanism of the observed strong heterocoordination in Au–Zn or homocoordination in Cu–Ni within the same framework. More importantly, we obtain all calculated quantities for the whole concentration range thus complimenting experimental evidence.

scholarly journals The adsorption of vapours on mercury. I. Non-polar substances

1946 ◽  
Vol 187 (1008) ◽  
pp. 53-73 ◽  
Keyword(s):  
Free Energy ◽  
Total Energy ◽  
Langmuir Equation ◽  
Phase Changes ◽  
Two Dimensional ◽  
Surface Phase ◽  
Standard State ◽  
Spreading Pressure ◽  
Benzene Toluene ◽  
Entropy Of Adsorption

Reversible results for the adsorption of benzene, toluene and n -heptane vapours on mercury have been obtained. The films were found to be gaseous and obeyed the Volmer eqution F ( A - b ) = kT , where F = spreading pressure, A =area per molecule and b = co-area. The possibility that the films might be immobile was considered and the Langmuir equation was applied but found unsatisfactory. A standard state for the surface phase was defined and the free energy, total energy and entropy of adsorption evaluated. The heat of adsorption was shown to increase with the amount on the surface. A number of phase changes were found to occur after the completion of monolayer adsorp­tion, the most striking being interpreted as the change over from ‘flat’ to ‘vertical’ adsorp­tion of the toluene molecules. Others were thought to be either two-dimensional condensation or adsorption of a second layer.

Probing Inclusion Complexes of Pentoxifylline and Pralidoxim inside Cyclic Oligosaccharides by Physicochemical Methodologies

2019 ◽  
Vol 233 (8) ◽  
pp. 1109-1127
Author(s):  
Biraj Kumar Barman ◽  
Kanak Roy ◽  
Mahendra Nath Roy
Keyword(s):  
Surface Tension ◽  
Free Energy ◽  
Inclusion Complexes ◽  
Apparent Molar Volume ◽  
Nmr Spectra ◽  
Drug Delivery Systems ◽  
Surface Tension Data ◽  
H Nmr ◽  
Ft Ir ◽  
Inclusion Phenomena

Abstract Structurally different Molecules namely Pentoxifylline and Pralidoxim were chosen along with α-cyclodextrin and β-cyclodextrin to study host-guest inclusion phenomena. The formations of host guest inclusion complexes were confirmed by studying 1H-NMR spectra, FT-IR spectra, apparent molar volume and viscosity co-efficient. The stabilities of inclusion complexes were compared calculating the binding constant from UV-VIS spectroscopic study. The 1:1 stoichiometry of the inclusion complexes were also determined by analysing the Jobs plot and surface tension data. The values for Gibbs’ free energy were found negative for both the processes. Based on all the above experiments the inclusion processes were found feasible for both the compounds. These types of inclusion complexes are of high interest in the field of research and industry as these are used as drug delivery systems.

TEMPERATURE DEPENDENCE OF SURFACE TENSION OF LIQUID CRYSTALS AT THE PHASE TRANSITION

1995 ◽  
Vol 09 (03n04) ◽  
pp. 237-242 ◽  
Author(s):  
R. MOLDOVAN ◽  
M. TINTARU ◽  
T. BEICA ◽  
S. FRUNZA ◽  
D. N. STOENESCU
Keyword(s):  
Experimental Data ◽  
Phase Transition ◽  
Surface Tension ◽  
Free Energy ◽  
Surface Layer ◽  
Order Parameter ◽  
Unit Area ◽  
Negative Slope ◽  
First Order ◽  
First Order Transition

The surface tension is calculated as the excess of the free energy per unit area, due to the presence of a surface layer, using Landau–de Gennes expansions, in the hypothesis of a first order transition in the bulk and taking into account the dependence of the surface free energy from the surface tilt angle. The surface order parameter is calculated and surface-ordered phase above the phase transition temperature has been found. A variety of calculated surface tension versus temperature curves with a jump at the phase transition, with positive or negative slope, well describing the experimental data from literature, have been attained.

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