Debye Length

Definition

The Debye length (<math>\kappa ^{-1}</math>), or Debye screening length, is the length scale over which charge carriers screen-out electric fields. One version of this equation when describing this length in a colloidal dispersion (or electrolyte solution) is:

<math> \kappa^{-1} = \sqrt{\frac{\varepsilon_0 \varepsilon_r k T}{2 N_A e^2 I}}</math>

where I is the ionic strength of the electrolyte, ε₀ is the permittivity of free space, ε_r is the dielectric constant, k is the Boltzmann constant, T is the absolute temperature in kelvins, N_A is Avogadro's number, and e is the elementary charge.

For more information on Peter Debye's original acoustic experiments, go to Electokinetics: Electroacoutic measurements.

References

• http://en.wikipedia.org/wiki/Debye_length#Debye_length_in_an_electrolyte
• R. Jones, "Soft Condensed Matter," Oxford University Press Inc., New York (2002).