scholarly journals A Generalization of Electromagnetic Fluctuation-Induced Casimir Energy

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Yi Zheng
Keyword(s):  
Thermal Fluctuations ◽  
Intermolecular Forces ◽  
Casimir Energy ◽  
Dispersion Force ◽  
Induced Dipole ◽  
Macroscopic Objects ◽  
Dissipative Media ◽  
London Dispersion ◽  
Quantum Mechanical Effects ◽  
London Dispersion Forces

Intermolecular forces responsible for adhesion and cohesion can be classified according to their origins; interactions between charges, ions, random dipole—random dipole (Keesom), random dipole—induced dipole (Debye) are due to electrostatic effects; covalent bonding, London dispersion forces between fluctuating dipoles, and Lewis acid-base interactions are due to quantum mechanical effects; pressure and osmotic forces are of entropic origin. Of all these interactions, the London dispersion interaction is universal and exists between all types of atoms as well as macroscopic objects. The dispersion force between macroscopic objects is called Casimir/van der Waals force. It results from alteration of the quantum and thermal fluctuations of the electrodynamic field due to the presence of interfaces and plays a significant role in the interaction between macroscopic objects at micrometer and nanometer length scales. This paper discusses how fluctuational electrodynamics can be used to determine the Casimir energy/pressure between planar multilayer objects. Though it is confirmation of the famous work of Dzyaloshinskii, Lifshitz, and Pitaevskii (DLP), we have solved the problem without having to use methods from quantum field theory that DLP resorted to. Because of this new approach, we have been able to clarify the contributions of propagating and evanescent waves to Casimir energy/pressure in dissipative media.

Pressure broadening studies on vibration-rotation bands II. The effective collision diameters

1959 ◽  
Vol 251 (1267) ◽  
pp. 475-485 ◽  
Keyword(s):  
Intermolecular Forces ◽  
Viscosity Data ◽  
Fundamental Vibration ◽  
Factors Affecting ◽  
Deuterium Chloride ◽  
Different Types ◽  
London Dispersion ◽  
Vibration Rotation ◽  
London Dispersion Forces ◽  
Effective Collision

Using the methods described in part I, the line widths in the fundamental vibration rotation bands of deuterium chloride and carbon monoxide have been measured, under conditions of self-broadening and also in the presence of added gases. The optical collision diameters have been calculated an d com pared with the molecular diameters derived from viscosity data. An attempt has been made to interpret the high effective collision diameters found in term s of intermolecular interactions of different types, and it is concluded that London dispersion forces, resonant dipole effects and quadrupole interactions may be important. The variatin of line width in aband as a function of J quantum number has been measured and considered in terms of these interactions. The results suggest th t further studies of this kind may throw further light not only upon the nature of intermolecular forces but also upon the factors affecting energy transfer in collision.

scholarly journals Molecular interactions in nanocellulose assembly

2017 ◽  
Vol 376 (2112) ◽  
pp. 20170047 ◽  
Author(s):  
Yoshiharu Nishiyama
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Molecular Modelling ◽  
Hydroxyl Group ◽  
Enthalpy Of Sublimation ◽  
Dispersion Force ◽  
Hydroxyl Groups ◽  
Range Interaction ◽  
Simple Arithmetic ◽  
London Dispersion

The contribution of hydrogen bonds and the London dispersion force in the cohesion of cellulose is discussed in the light of the structure, spectroscopic data, empirical molecular-modelling parameters and thermodynamics data of analogue molecules. The hydrogen bond of cellulose is mainly electrostatic, and the stabilization energy in cellulose for each hydrogen bond is estimated to be between 17 and 30 kJ mol −1 . On average, hydroxyl groups of cellulose form hydrogen bonds comparable to those of other simple alcohols. The London dispersion interaction may be estimated from empirical attraction terms in molecular modelling by simple integration over all components. Although this interaction extends to relatively large distances in colloidal systems, the short-range interaction is dominant for the cohesion of cellulose and is equivalent to a compression of 3 GPa. Trends of heat of vaporization of alkyl alcohols and alkanes suggests a stabilization by such hydroxyl group hydrogen bonding to be of the order of 24 kJ mol −1 , whereas the London dispersion force contributes about 0.41 kJ mol −1  Da −1 . The simple arithmetic sum of the energy is consistent with the experimental enthalpy of sublimation of small sugars, where the main part of the cohesive energy comes from hydrogen bonds. For cellulose, because of the reduced number of hydroxyl groups, the London dispersion force provides the main contribution to intermolecular cohesion. This article is part of a discussion meeting issue ‘New horizons for cellulose nanotechnology’.

scholarly journals Gas-Solid Interaction

1968 ◽  
Vol 23 (7) ◽  
pp. 979-984 ◽  
Author(s):  
Manlio Sanesi ◽  
Vittoriano Wagner
Keyword(s):  
Adsorption Energy ◽  
Surface Coverage ◽  
Aluminium Oxide ◽  
Dispersion Forces ◽  
Heats Of Adsorption ◽  
Linear Alkanes ◽  
London Dispersion ◽  
London Dispersion Forces

The heats of adsorption on weakly activated γ-aluminium oxide for a number of linear alkanes (from n-butane to n-nonane) and for 2.2.4-trimethylpentane have been determined by GSC and extrapolated to zero surface coverage.The dependance of the adsorption energy on the number of carbon atoms is discussed on the basis of the bidimensional gas model: it is shown that the interactions of the adsorbates with the oxidic surface are mainly due to London dispersion forces.

London Dispersion Forces between Unlike Molecules

1952 ◽  
Vol 20 (11) ◽  
pp. 1812-1812 ◽  
Author(s):  
James F. Hornig ◽  
Joseph O. Hirschfelder
Keyword(s):  
Dispersion Forces ◽  
London Dispersion ◽  
London Dispersion Forces

The role of dispersion type metal⋯π interaction in the enantiotropic phase transition of two polymorphs of tris-(thienyl)bismuthine

2017 ◽  
Vol 46 (39) ◽  
pp. 13492-13501 ◽  
Author(s):  
A. M. Preda ◽  
W. B. Schneider ◽  
D. Schaarschmidt ◽  
H. Lang ◽  
L. Mertens ◽  
...  
Keyword(s):  
Phase Transition ◽  
Dft Calculations ◽  
Dispersion Forces ◽  
Model Compounds ◽  
London Dispersion ◽  
London Dispersion Forces

Bi(2-C4H3S)3 shows an enantiotropic phase transition that is dominated by London dispersion forces. DFT calculations on model compounds were carried out in order to investigate the competition between Bi⋯S and Bi⋯π heteroarene interaction.

Counterintuitive Interligand Angles in the Diaryls E{C6H3-2,6-(C6H2-2,4,6-iPr3)2}2(E = Ge, Sn, or Pb) and Related Species: The Role of London Dispersion Forces

2018 ◽  
Vol 37 (13) ◽  
pp. 2075-2085 ◽  
Author(s):  
Madison L. McCrea-Hendrick ◽  
Markus Bursch ◽  
Kelly L. Gullett ◽  
Leonard R. Maurer ◽  
James C. Fettinger ◽  
...  
Keyword(s):  
Related Species ◽  
Dispersion Forces ◽  
London Dispersion ◽  
London Dispersion Forces

scholarly journals London dispersion forces without density distortion: a path to first principles inclusion in density functional theory

2020 ◽  
Vol 224 ◽  
pp. 145-165
Author(s):  
Derk Pieter Kooi ◽  
Paola Gori-Giorgi
Keyword(s):  
Ground State ◽  
First Principles ◽  
Density Functional ◽  
Dispersion Forces ◽  
Density Functionals ◽  
Functional Theory ◽  
Exchange Correlation ◽  
State Densities ◽  
London Dispersion ◽  
London Dispersion Forces

We analyse a path to construct density functionals for the dispersion interaction energy from an expression in terms of the ground state densities and exchange–correlation holes of the isolated fragments.

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