POLARIZED RAMAN-SPECTRA OF DIGLYCINE NITRATE SINGLE-CRYSTAL IN THE LATTICE-VIBRATION REGION

Polarized Raman spectra (300-10 cm-1) of a diglycine nitrate (DGN) sin gle crystal were measured in the paraelectric (at 300 and 210 K) and f erroelectric (at 150 and 26 K) phases. The Raman spectra of the parael ectric phase are very simple and exhibit broadening of the Rayleigh li ne, especially in the (aa*) spectra. The Raman spectra of the ferroel ectric phase were found to exhibit many more bands while the broadenin g of the Rayleigh line disappears. The origin of this phenomenon is di scussed.