RAMAN-STUDY OF A PHASE-TRANSITION IN SOLID CHLORODIFLUOROMETHANE

Raman spectra of solid chlorodifluoromethane at temperatures between 20 and 80 K in both the lattice and internal mode regions are reported. Evidence of a solid-state phase transition at 60 +/- 5 K is presented. In both phases, the multiplet structure of the internal fundamentals is shown to originate from crystal field rather than isotopic effects for most modes, which indicates that both phases are ordered with fairly large unit cells and that the transition is therefore of a displacive type.