Neutron and Infrared Spectra of HCrO2 and DCrO2

Abstract

The vibrational spectra of HCrO₂ and DCrO₂ have been investigated by the energy‐gain scattering of cold neutrons, and by infrared absorption spectra from 4000–30 cm⁻¹. The infrared measurements are in agreement with previous results above 300 cm⁻¹. In addition, no absorptions are observed between 300 and 30 cm⁻¹, a region not covered in previous measurements. These results appear to support previous evidence for asymmetric hydrogen bonds in DCrO₂ and essentially symmetric bonds in HCrO₂. The neutron spectra exhibit a number of maxima, including a band peaked at about 225 cm⁻¹ in HCrO₂ (and a less intense peak around 180 cm⁻¹ in DCrO₂), probably due to low‐frequency optic lattice modes. A comparison of the neutron and infrared results appears to raise some uncertainty concerning the assumption of symmetric hydrogen bonds in HCrO₂.