Structural investigations of the ferroelectric glycinium hydrogenphosphite (GPI) crystal and its deuterated analogue (DGPI). II: Polarised vibrational studies at room temperature

Polarised IR and Raman spectra of glycinium hydrogenphosphite (GPI) crystal and its deuterated analogue (DGPI) were measured at room temperature. The polarised IR spectra were measured by transmission and specular reflection method. Assignment of the bands is proposed on the basis of the oriented gas model approximation. Simultaneous analysis of the Raman and IR spectra for the stretching P-H bonds does not indicate on C-i site symmetry for the interphosphite hydrogen bonds in the paraelectric phase. The vibrational spectra of the DGPI crystal do not prove a presence of two so different glycinium cations and hydrogenphosphite anions, as it follows from the X-ray data. (C) 2004 Elsevier B.V. All rights reserved.