Structural transformation studies of AgNO3 by Raman and infrared spectroscopy

The fundamental modes of the NO−3 ion were studied using AgNO3 single crystal samples at low temperatures. The Raman and IR spectra of the in-plane bending mode ν4 at 730 cm−1 proved to be the most informative, and two possible phase transitions were found. Soft mode behaviour was found for the ν4 mode, the ν3 asymmetric stretch mode and the 2ν3 overtones.