User:Greatreddragonfly/sandbox/project 02

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What is it? material property, general order of magnitude, non-retarded Hamaker constant

where does it come for? derivation

What is it used for? determine relative strength van der Waal

How is it measured? experiments, Lifshitz theory

Source 01
''Soft Condensed Matter - Richard A. L. Jones → 4. colloidal dispersion → 4.3 forces between colloidal particles → 4.3.2 Van der Waals forces''

″The Hamaker constant is a material property with the dimensions of energy; for many materials its order of magnitude is around 10^-19 J.″

"Full calculations of the van der Waals force between two bodies are complicated and require detailed knowledge of the electrical properties of the materials. The most usual approach is to use the expression of eqn 4.18, ..., using various approximate expressions derived from the Lifshitz theory for the Hamaker constant A."

Source 02
"The Hamaker constant is an important parameter of the London-van der Waals forces in describing particle interactions including coagulation, flotation, dispersion, and ordering. For many materials, Hamaker constants have now been compiled. For calculation of Hamaker constants, many methods are proposed: for example, colloid chemical methods based on flocculation of particles, interaction of two crossed metal wires, and equilibrium or dynamic film thickness measurements; determination from surface tension measurements; Theological method; and measurements of solid-solid interactions between macroscopic bodies at long distances. In this section, one of the flocculation methods with monodispersed particles will be introduced."

Source 03
(probably don't use)

"Hamaker constants represent the London Dispersion Force of the van der Waals attraction between two materials. Because London Dispersion Forces arise from the interaction between fluctuating dipoles whose frequencies lie in the optical and UV regions of the spectrum, Hamaker constants may be calculated from the complex dielectric constants measured in the optical/UV portions of the spectrum."

Source 04
(don't use)

"The van der Waals interaction between different materials depends on their differences in optical properties and can be characterized by the so-called Ha-maker constant. Hamaker constants either can be calculated from dielectric and spectroscopic information of the materials using the Lifshitz theory or can be determined experimentally."

"A common approach to treating retardation in dispersion forces is to define an effective Hamaker constant that is not constant but depends on separation distance."