On the theory of the Debye and the far infrared absorption of polar fluids

The variation with frequency of the electric polarizability of the itinerant oscillator model of polar liquids is calculated. The calculation is effected by means of the Langevin equation and linear response theory and full account is taken of inertial effects throughout. The results are qualitatively in accordance with experiment and show how the microwave Debye absorption peak and the terahertz resonance absorption peak may be linked analytically by means of a model based on the classical theory of the Brownian movement in the presence of an external force.