IR and Raman spectra of AgNO3 at low temperatures

Abstract The IR spectra of AgNO 3 were recorded using single‐crystal samples and polarized radiation. More detailed information was obtained than that reported in previous studies using polycrystalline samples. The very strong IR absorption bands of the ν 3 and ν 2 modes were studied by polarized reflection measurements. Raman spectra of AgNO 3 were also recorded and used to provide supplementary data. Better assignments for the components of the fundamental modes were obtained using the polarized spectra, and some isotope and combination bands were also observed and assigned. The present data allow a better understanding of the splittings of the fundamental modes. The low‐temperature phase showed a softening of the ν 3 and ν 4 modes as the crystals were cooled below the transition temperature (140 K), and this suggests a limited ( P , T ) range of stability for this phase.