Correct Derivation of the Analogue of Lanjavin's Formula

Abstract

In the proposed work, the derivation of the Langevin formula for the average value of the dipole moment is analyzed. The basic assumption about the uniform distribution of dipoles at the angles when deriving the formula is not correct, since the dipoles are in a homogeneous electric field that sets the selected direction. Accounting for the selected direction leads to a significant complication of the mathematical apparatus, but will allow you to get a more correct expression for the average dipole moment.