Structure of N2-CH4 cryoalloys

Transmission electron diffraction is used to study the structure of N2-CH4 alloys over the entire range of mutual concentrations. Samples were prepared in situ by deposition of a gaseous mixture on aluminum and carbon substrates at temperatures of 19 and 5 K. The solubility limits for the components are less than 6% methane in crystalline nitrogen and 35% nitrogen in solid methane. The dependence of the lattice parameter on composition is studied in terms of a three-cluster model for low concentrations of the components in the solutions. The effect of impurity CH4 molecules on the orientational ordering of N2 molecules in the solutions is investigated.