The Quantum Theory of the Dielectric Constant of Hydrogen Chloride and Similar Gases.

Here e is the dielectric constant of the gas, F the strength of the applied field, N the number of molecules in unit volumes, ,u the permanent electric moment of a molecule, and a the coefficient of induced polarization of a molecule; cos 0 is the average value of cos 0 for all molecules in the gas, and cos 6 is the time-average of cos 0 for one molecule in a given state of motion, 0 being the angle between the dipole axis and the lines of force of the applied field. On the basis of the classical theory it was shown by Debye2 that cos 0 is given by the Langevin function