Orientational ordering in methane condensates in mesoporous SiO2modifications at low temperatures

The rotational spectra of CH 4 at low temperatures have been used to investigate the disordering influence of a restricted geometry on the orientational structure of methane condensates in silicagels and Controlled Pore Glasses. A cross-over from complete orientational disorder to the partially ordered phase II of pure methane was observed with increasing pore diameter d at d ∼120 A.