Isotope-dependent crystalline phases at ambient temperature: Spectroscopic and calorimetric evidence for a deuteration-induced phase transition at 320 K in α-DCrO2

Abstract The heat capacities of HCrO 2 and DCrO 2 have been measured at temperatures between 5 and 360 K. A lambda anomaly occurred at 320 K for DCrO 2 but not for HCrO 2 . Infrared spectra were recorded at temperatures between 5 and 405 K. The spectrum of DCrO 2 changed at 320 K with respect to the peak wave-number and splitting of some of the vibrations, while those of HCrO 2 depended smoothly on temperature. These experimental results are discussed in terms of a deuteration-induced phase transition.