Abstract: | A complete infrared study of the mixed crystal system of AgNO3 and Fe(NO3)3 is carried out in the region 400–4000 cm?1. The study includes internal fundamental normal vibrations of the NO3? ion in the ordered and disordered phases of AgNO3 at different values of the ferric concentration, I.R. spectra, spectral band shape intensities, and frequencies of the internal modes as functions of the ferric ion concentration. Special attention is paid to bending mode, combination mode, asymmetric stretching mode, and over-tone. The rotational energy barrier is determined at different concentration of the ferric ions in the system of AgNO3-Fe(NO3)3. |