ABSTRACT
Let us consider a gas of neutral atoms interacting through a short-range binary potential. At high enough temperatures and low enough pressures, the gas is dilute. Each atom moves as if it were essentially free, apart from infrequent collisions with other atoms or with the container walls. The system is well described by the elementary kinetic theory of gases. It displays the usual properties of a classical gas; the specific heat Cv is temperature independent; in the case of fermions (particles with spin) the spin susceptibility varies inversely with the temperature, according to Curie’s law.
