Low-temperature infrared absorption of gaseous N2 and N2 + H2 in the 2.0-2.5 micron region - application to the atmospheres of Titan and Triton

Temperatures representative of the atmospheres of Titan and Triton are used in the present laboratory study of collision-induced spectra of both pure N2 and N2 + H2 mixtures in the 2.0-2.5 micron spectral range. In Titan's case, it is found that both pure and mixture absorptions are likely to be significant and of approximately equal strength. In the case of Triton, about whose atmosphere much more remains to be determined, the observed N2 absorption feature at 2.16 microns may be due to the gas rather than to the previously suggested liquid nitrogen. 31 refs