Raman spectrum and dielectric relaxation in K₄Fe(CN)₆ · 3 H₂O

Abstract

Abstract The temperature dependence of the two Raman active modes at 62 and 126 cm −1 corresponding to the symmetry B g /A″ (z) is investigated. In the vicinity of the phase transition point ( T C = 249 K) the mode bandwidths undergo a sharp increase which is assigned to the reduction of the barrier height characterizing the water Brownian motion. A semi‐empirical expression for the temperature dependence of the barrier height is given. Mason's relaxation theory is used to correlate the temperature behaviour of the barrier with the dielectric constant of KFCT as function of temperature and frequency.