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Dielectric polarization evolution equations and relaxation times



James R. Baker-Jarvis, Billy F. Riddle, Michael D. Janezic


In this paper we develop a model that can describe broadband dielectric response, and includes frequency-dependent loss and the effects of the local electric field. The model is based on a correlation-function approach that we previously developed using statistical-mechanical theory. We develop a very general integro-differential equation for the polarization. The Laplace-transformed form of this equation contains a frequency-dependent relaxation time. We show that the real part of the relaxation is negative; however; near resonance the imaginary part of the relaxation time is positive. This is due to the effects of the local field on the molecular short-range restoring forces. We present illustrative examples for the harmonic oscillator and derive the expressions for the frequency-dependent relaxation times and a time-domain integro-differential equation for the Cole-Davidson model. We extract the real and imaginary parts of the relaxation time from alcohol permittivity data. We also develop a generalize Lyddane-Sachs-Teller relationship.
Physical Review A (Atomic, Molecular and Optical Physics)


dielectric, linear response, loss factor, nonequilibrium, permittivity relaxation.


Baker-Jarvis, J. , Riddle, B. and Janezic, M. (2007), Dielectric polarization evolution equations and relaxation times, Physical Review A (Atomic, Molecular and Optical Physics), [online], (Accessed May 22, 2024)


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Created May 25, 2007, Updated June 2, 2021