Collision-Induced Absorption of Compressed Gases in the Far Infrared, Part Ii

The induced spectra of compressed helium–argon and neon–argon mixtures, and of compressed hydrogen, nitrogen, and oxygen have been measured in the frequency region 20 to 400 cm −1 . The far-infrared spectra consist of a translational branch and a rotational branch which overlap, except in the rare-gas mixtures where only the translational component exists. The latter is a broad band which extends from zero frequency to about 500 cm −1 , with a maximum near 150 cm −1 in the room-temperature gas. In the case of hydrogen the translational branch is readily distinguished from the rotational branch because it lies at a lower frequency than the latter. In the case of oxygen and nitrogen the spacing between the rotational lines is small and the translational and rotational branches overlap completely.