Beschreibung:
<jats:title>Abstract</jats:title><jats:p>A variational procedure for the solution of the Boltzmann equation with an arbitrary number of variational parameters is developed. In the frame of the method it is possible to carry out the optimization of trial function, as well as to check the convergence of the solution. It is shown that in semimetals the probability matrix of charge carrier scattering on acoustic phonons entering the expression for the collision operator has a non‐diagonal form in the coordinate system of the effective mass tensor. General expressions are obtained for the transport coefficients allowing to determine their numerical values.</jats:p>