Weak infrared bands in solid CH4-II

Abstract
The spectrum of solid methane in its partially ordered phase II was studied between 1000 and 3500 cm−1 with improved sensitivity. The librational band of D2d molecules associated with the ν3 and ν4 mode could be observed in detail, and evidence of induced absorption was found in the region of the infrared inactive ν2 mode. The first infrared spectra in solid CH4 of the overtone 2ν4 and of the combination band ν2+ν4 are also reported.