The rototranslational absorption spectrum of gaseous N₂ is analyzed, considering quadrupolar and hexadecapolar induction mechanisms. The available experimental data are accounted for by using a line-shape analysis in which empirical profiles describe the single-line translational profiles. We thus derive the simple procedure that allows one to predict the N₂ spectrum at any temperature. On the basis of the results obtained for the pure gas, we also propose a procedure to compute the far-infrared spectrum of the N₂–Ar gaseous mixture. The good agreement between computed and experimental N₂–Ar data indicates that it is possible to predict the far-infrared absorption induced by N₂ on the isotropic polarizability of any interacting partner.