Anomalous properties of crystalline methane in the range of 60–70 K

Mechanical, structural, thermal, and spectral properties of solid methane in the temperature range 0.5$T_{\mathrm{tr}}$–$T_{\mathrm{tr}}$ ($T_{\mathrm{tr}}$ is the triple point) at the equilibrium vapor pressure have been analyzed. It has been shown that the totality of observed anomalies in the temperature range of 60–70 K can be explained by the existence of collective rotational degrees of freedom in solid methane.