Simple Semiempirical Method of Calculating van der Waals Interactions in Thin Films from Lifshitz Theory

1976 ◽  
Vol 31 (12) ◽  
pp. 1584-1588 ◽  
Author(s):  
Chr. St. Vassilieff ◽  
I. B. Ivanov
Keyword(s):  
Experimental Data ◽  
Thin Films ◽  
Empirical Formula ◽  
Van Der Waals ◽  
Semiempirical Method ◽  
Simple Expression ◽  
Van Der Waals Interactions ◽  
Dispersion Dependence ◽  
Satisfactory Accuracy ◽  
Lifshitz Theory

AbstractThe influence of different representations of the dispersion dependence ε (i ξ) on calculating van der Waals interactions from Lifshitz theory is studied. It is shown that with satisfactory accuracy ε (i ξ) can be described by means of Krupp's empirical formula [ε (i ξ) -1]/[ε (i ξ) +1] = a · exp(-b ξ). Making use of that formula a simple expression for the Hamaker function A (h, T) is obtained. Numerical calculations are carried out, the results being compared with those of other authors and with experimental data.

Concisely modularized assembling of graphene-based thin films with promising electrode performance

2019 ◽  
Vol 3 (7) ◽  
pp. 1462-1470 ◽  
Author(s):  
Weiwei Wei ◽  
Rohit L. Vekariy ◽  
Chuanting You ◽  
Yafei He ◽  
Ping Liu ◽  
...  
Keyword(s):  
Thin Films ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Double Layer ◽  
Van Der Waals ◽  
Cellulose Nanofibers ◽  
Van Der Waals Interactions ◽  
Electrode Performance ◽  
Reduced Graphene

Highly dense thin films assembled from cellulose nanofibers and reduced graphene oxide via van der Waals interactions to realize ultrahigh volumetric double-layer capacitances.

Solvation of a water molecule in cyclohexane and water

2001 ◽  
Vol 79 (2) ◽  
pp. 105-109 ◽  
Author(s):  
Giuseppe Graziano
Keyword(s):  
Experimental Data ◽  
Water Molecule ◽  
Standard Gibbs Energy ◽  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
Solvent Interactions ◽  
Turn On ◽  
Standard Gibbs Energy Change ◽  
Water Solvent ◽  
Work Of Cavity Creation

Reliable values for the thermodynamic functions associated with the solvation of a water molecule in its own liquid phase and in cyclohexane, at 25°C, are obtained using experimental data from different investigations. They are successfully rationalized by means of a general theory of solvation. The standard Gibbs energy change is given by the balance of two contrasting terms: the work to create a cavity in the solvent suitable to host the water molecule; and the work to turn on the water-solvent interactions. It proves that the work of cavity creation is largely overwhelmed by the formation of two H-bonds in liquid water, whereas it is almost exactly counterbalanced by the establishment of van der Waals interactions in liquid cyclohexane.Key words: water, cavity creation, H-bonds, van der Waals interactions.

scholarly journals Calculation of Hamaker Constants in Nonaqueous Fluid Media

2000 ◽  
Vol 624 ◽  
Author(s):  
Nelson Bell ◽  
Duane Dimos
Keyword(s):  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Dielectric Materials ◽  
Van Der Waals Interactions ◽  
Experimental Measurements ◽  
Dielectric Data ◽  
Fluid Media ◽  
Lifshitz Theory ◽  
Hamaker Constants

ABSTRACTCalculations of the Hamaker constants representing the van der Waals interactions between conductor, resistor and dielectric materials are performed using Lifshitz theory. The calculation of the parameters for the Ninham-Parsegian relationship for several non-aqueous liquids has been derived based on literature dielectric data. Discussion of the role of van der Waals forces in the dispersion of particles is given for understanding paste formulation. Experimental measurements of viscosity are presented to show the role of dispersant truncation of attractive van der Waals forces

scholarly journals Calculation of Hamaker Constants in Nonaqueous Fluid Media

2000 ◽  
Vol 625 ◽  
Author(s):  
Nelson Bell ◽  
Duane Dimos
Keyword(s):  
Van Der Waals ◽  
Van Der Waals Forces ◽  
Dielectric Materials ◽  
Van Der Waals Interactions ◽  
Experimental Measurements ◽  
Dielectric Data ◽  
Fluid Media ◽  
Lifshitz Theory ◽  
Hamaker Constants

AbstractCalculations of the Hamaker constants representing the van der Waals interactions between conductor, resistor and dielectric materials are performed using Lifshitz theory. The calculation of the parameters for the Ninham-Parsegian relationship for several non-aqueous liquids has been derived based on literature dielectric data. Discussion of the role of van der Waals forces in the dispersion of particles is given for understanding paste formulation. Experimental measurements of viscosity are presented to show the role of dispersant truncation of attractive van der Waals forces.

Van der Waals, interactions in multicomponent homogeneous thin films

1978 ◽  
Vol 256 (11) ◽  
pp. 1142-1143 ◽  
Author(s):  
I. B. Ivanov ◽  
Chr St. Vassilieff
Keyword(s):  
Thin Films ◽  
Van Der Waals ◽  
Van Der Waals Interactions

Thermodynamic Stability of Hexagonal and Rhombohedral Bn at Cvd Conditions from Van der Waals Corrected First Principles Calculations

2019 ◽  
Author(s):  
Henrik Pedersen ◽  
Björn Alling ◽  
Hans Högberg ◽  
Annop Ektarawong
Keyword(s):  
Thin Films ◽  
Thermodynamic Stability ◽  
First Principles ◽  
Thermal Equilibrium ◽  
Density Functional ◽  
Van Der Waals ◽  
Chemical Vapor ◽  
First Principles Calculations ◽  
Functional Theory ◽  
The Stability

Thin films of boron nitride (BN), particularly the sp<sup>2</sup>-hybridized polytypes hexagonal BN (h-BN) and rhombohedral BN (r-BN) are interesting for several electronic applications given band gaps in the UV. They are typically deposited close to thermal equilibrium by chemical vapor deposition (CVD) at temperatures and pressures in the regions 1400-1800 K and 1000-10000 Pa, respectively. In this letter, we use van der Waals corrected density functional theory and thermodynamic stability calculations to determine the stability of r-BN and compare it to that of h-BN as well as to cubic BN and wurtzitic BN. We find that r-BN is the stable sp<sup>2</sup>-hybridized phase at CVD conditions, while h-BN is metastable. Thus, our calculations suggest that thin films of h-BN must be deposited far from thermal equilibrium.

Crystal Structures of Two New Cyclosporin Clathrates

2000 ◽  
Vol 65 (12) ◽  
pp. 1950-1958 ◽  
Author(s):  
Michal Hušák ◽  
Bohumil Kratochvíl ◽  
Ivana Císařová ◽  
Alexandr Jegorov
Keyword(s):  
Crystal Structures ◽  
Methyl Ether ◽  
Van Der Waals ◽  
Van Der Waals Interactions ◽  
Solvent Molecules ◽  
Butyl Methyl Ether

Two isomorphous clathrates formed by dihydrocyclosporin A or cyclosporin V with tert-butyl methyl ether are reported and compared with the structures of related P21-symmetry cyclosporin clathrates. The cyclosporin molecules in both structures are associated via van der Waals interactions forming cavities occupied by solvent molecules (cyclosporin : tert-butyl methyl ether is 1 : 2).

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