2008ApJ...686.1480B

We studied icy CH₄ and its mixtures with N₂(temperature 16-40 K), using near-IR transmittance spectroscopy (1.0-3.6 µm), and monitoring the film growth using interference patterns of two lasers. We measured peak position, full width at half-maximum, and strengths of the methane bands, and density and real refractive index of the icy films.
Result. confirm and extend but also partially contradict previous studies on similar mixtures. Experimental data can be applied to interpret observations of solar system (trans-Neptunian objects) and interstellar ices, where methane and nitrogen are believed to be present. We predict the optical depths of two methane NIR bands in the line of sight of some dense molecular clouds.