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An Ion of charge and a nonpolar molecule of polarizability . The Lifshitz theory can be expressed as an effective Hamaker constant in the van der Waals theory. Consider, for example, the interaction between an ion of charge Q {\textstyle Q} , and a nonpolar molecule with polarizability α 2 {\textstyle \alpha _{2}} at distance r {\textstyle r} .
Polarizability increases down on columns of the periodic table. [9] Likewise, larger molecules are generally more polarizable than smaller ones. Water is a very polar molecule, but alkanes and other hydrophobic molecules are more polarizable. Water with its permanent dipole is less likely to change shape due to an external electric field.
where μ is the electric dipole moment of the effectively polarized water molecule (2.35 D for the SPC/E model), μ 0 is the dipole moment of an isolated water molecule (1.85 D from experiment), and α i is an isotropic polarizability constant, with a value of 1.608 × 10 −40 F·m 2. Since the charges in the model are constant, this ...
London dispersion forces are also known as 'dispersion forces', 'London forces', or 'instantaneous dipole–induced dipole forces'. The strength of London dispersion forces is proportional to the polarizability of the molecule, which in turn depends on the total number of electrons and the area over which they are spread.
For example, nine of the nineteen L-amino acids naturally occurring in proteins are, despite the L- prefix, actually dextrorotary (at a wavelength of 589 nm), and D-fructose is sometimes called "levulose" because it is levorotary. The D- and L- prefixes describe the molecule as a whole, as do the (+) and (−) prefixes for optical rotation.
The waves propagate over an elliptic-shaped underwater shoal on a plane beach. This example combines several effects of waves and shallow water, including refraction, diffraction, shoaling and weak non-linearity. In fluid dynamics, the Boussinesq approximation for water waves is an approximation valid for weakly non-linear and fairly long waves.
Dispersion of gravity waves on a fluid surface. Phase and group velocity divided by shallow-water phase velocity √ gh as a function of relative depth h / λ. Blue lines (A): phase velocity; Red lines (B): group velocity; Black dashed line (C): phase and group velocity √ gh valid in shallow water.
Figure 1 shows the scattering length density for water and various biological macromolecules as a function of the deuterium concentration. (Adapted from. [2]) Biological samples are usually dissolved in water, so their hydrogens are able to exchange with any deuteriums in the solvent. Since the overall scatter of a molecule depends on the ...