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In the CGS system of units the Clausius–Mossotti relation is typically rewritten to show the molecular polarizability volume ′ = which has units of volume [m 3]. [2] Confusion may arise from the practice of using the shorter name "molecular polarizability" for both α {\displaystyle \alpha } and α ′ {\displaystyle \alpha '} within ...
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.
In water, this is where the absorptive index starts to drop sharply, and the minimum of the imaginary permittivity is at the frequency of blue light (optical regime). At high frequencies (such as UV and above), molecules cannot relax, and the energy is purely absorbed by atoms, exciting electron energy levels.
Yet another definition exists [5] where and are expressed in the cgs system and is still defined as =. Using the cgs units gives α {\displaystyle \alpha } the dimension of a volume, as in the first definition, but with a value that is 4 π {\displaystyle 4\pi } lower.
Molar refractivity, [1] [2], is a measure of the total polarizability of a mole of a substance. For a perfect dielectric which is made of one type of molecule, the molar refractivity is proportional to the polarizability of a single molecule of the substance. For real materials, intermolecular interactions (the effect of the induced dipole ...
For instance, dichloromethane has a value of ε r of 9.08 (20 °C) and is rather poorly soluble in water (13 g/L or 9.8 mL/L at 20 °C); at the same time, tetrahydrofuran has its ε r = 7.52 at 22 °C, but it is completely miscible with water.
Carbonated drinks known as sparkling, fizzy, seltzer and soda waters are thought to impact the waistline. A new study weighs in, but don’t expect too much. What you should know about carbonated ...
One difference between the Gaussian and SI systems is in the factor 4π in various formulas that relate the quantities that they define. With SI electromagnetic units, called rationalized, [3] [4] Maxwell's equations have no explicit factors of 4π in the formulae, whereas the inverse-square force laws – Coulomb's law and the Biot–Savart law – do have a factor of 4π attached to the r 2.