The thermal conductivity of polyatomic molecules

We show that by means of a linear transformation of the trial functions in the second approximation to the distribution function, a simple expression for the thermal conductivity of polyatomic molecules can be obtained. This is made possible using our results of state-selective measurements of the nonequilibrium distribution in a heat conducting gas. Also a direct relationship between the pure gas transport coefficients can be deduced, which gives an accurate description of both monatomic and polyatomic gases. This is illustrated by a comparison between calculated and experimental data of the thermal conductivity.