The vibrational spectra of solid II ethane and ethane-d6

Abstract

Mid‐infrared spectra and Raman spectra are reported for solid II ethane, ethane‐d₆, and their mutual solid solutions, at temperatures near 20 K. The results are consistent with a recent x‐ray crystal structure determined for this phase of ethane. Observed vibrations are assigned and compared with several different lattice‐dynamical calculations based on various atom–atom potentials. External vibrations are reproduced moderately well by several potentials, one of which has electrical charges on the atoms. Splittings of internal vibrations are not fit well. Several puzzling discrepancies are noted in the Raman intensities for the solid.