FIR Spectra of [Ni(H2O)6](ClO4)2 and [Ni(D2O)6](ClO4)2 at Various Temperatures

Abstract

Low frequency vibrations in [Ni(H2O)6](ClO4)2 and [Ni(D2O)6](ClO4)2 were measured by the FIR Fourier Transform Spectroscopy method. They were compared with those obtained by the IINS method. No evidence of proton glass discovered by the IINS was observed via the FIR method. By applying the band contour method, the barrier to rotation U act for H2O groups in [Ni(H2O)6](ClO4)2 crystals was determined. A III–II phase transition mechanism was proposed.