Debye relaxation
E518986
Debye relaxation is a model in dielectric physics that describes how polar molecules in a material respond over time to changes in an external electric field, characterized by a single relaxation time.
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
dielectric relaxation model
ⓘ
phenomenological model ⓘ physical model ⓘ |
| appliesTo |
polar dielectrics
ⓘ
polar liquids ⓘ some polar polymers ⓘ |
| associatedWith | rotational diffusion of dipoles ⓘ |
| assumes |
Markovian dynamics
ⓘ
exponential decay of polarization ⓘ linear response ⓘ non-interacting dipoles ⓘ |
| characterizedBy | single relaxation time ⓘ |
| contrastWith | non-Debye relaxation ⓘ |
| describes | time-dependent response of polar molecules to an external electric field ⓘ |
| field |
condensed matter physics
ⓘ
dielectric physics ⓘ |
| frequencyDomainBehavior |
high-frequency permittivity approaches epsilon_infinity
ⓘ
low-frequency permittivity approaches epsilon_s ⓘ |
| generalizedBy |
Cole–Cole model
NERFINISHED
ⓘ
Cole–Davidson model NERFINISHED ⓘ Havriliak–Negami model NERFINISHED ⓘ |
| governingEquation | dP/dt = -(P - P_eq)/tau ⓘ |
| hasMathematicalForm | complex permittivity epsilon(omega) = epsilon_infinity + (epsilon_s - epsilon_infinity) / (1 + i omega tau) ⓘ |
| hasParameter |
high-frequency permittivity epsilon_infinity
ⓘ
relaxation time tau ⓘ static permittivity epsilon_s ⓘ |
| hasType | single-time-constant relaxation ⓘ |
| introducedBy | Peter Debye NERFINISHED ⓘ |
| limitation |
cannot describe broad relaxation time distributions
ⓘ
ignores cooperative molecular motions ⓘ often inadequate for complex polymers ⓘ |
| neglects |
dipole–dipole interactions
ⓘ
distribution of relaxation times ⓘ |
| predicts |
Lorentzian loss peak as a function of frequency
ⓘ
dispersion of real part of permittivity ⓘ |
| relatedTo | Arrhenius temperature dependence of relaxation time ⓘ |
| relatesQuantity |
angular frequency
ⓘ
complex permittivity ⓘ dielectric loss ⓘ |
| timeDomainForm | P(t) = P_0 exp(-t/tau) for step change in field ⓘ |
| usedIn |
dielectric spectroscopy
ⓘ
material characterization ⓘ microwave engineering ⓘ molecular dynamics modeling ⓘ |
| usedToExtract |
activation energies for dipolar relaxation
ⓘ
molecular dipole relaxation times from dielectric data ⓘ |
| yearProposed | 1929 ⓘ |
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.