Rotational energy transfer between two N2 molecules is a fundamental process of some importance . Exchange is expected to play a role , but its importance is somewhat uncertain . Rotational energy transfer cross sections of N2 also have applications in many other fields including modeling of aerodynamic flows , laser operations , and linewidth analysis in nonintrusive laser diagnostics . A number of N2 - N2 rigid rotor potential energy surface ( PES ) has been reported in the literature .