Dynamical properties of crystals of Sr(NO3)2, Ba(NO3)2, and Pb(NO3)2. II. Temperature dependence of the infrared spectra

Abstract
Reflective infrared spectra of three single crystals of strontium nitrate, barium nitrate, and lead nitrate are investigated between 10 and 3500 cm−1 at temperatures from 10 to 293 K. The temperature behaviour of the dispersion parameters, frequencies, strengths, and damping obtained from classical dispersion relation is analyzed in order to compare, first the miscellaneous modes of the same crystal and then of different crystals. The case of Sr(NO3)2 which presents an anomaly in the infrared spectra corresponding to a phase transition is studied in more depth.