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Polarized Raman scattering and phase transition studies of n ‐diethylenediammonium monohydrogenmonophosphate dihydrate
Author(s) -
Elleuch S.,
Feki H.,
Abid Y.,
Mlayah A.
Publication year - 2006
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1538
Subject(s) - raman spectroscopy , differential scanning calorimetry , raman scattering , chemistry , phase transition , molecular vibration , ion , analytical chemistry (journal) , hydrogen bond , phase (matter) , atmospheric temperature range , crystallography , crystal (programming language) , molecule , condensed matter physics , optics , thermodynamics , physics , organic chemistry , computer science , programming language
Polarized Raman scattering studies at room temperature were carried out on N ‐diethylenediammonium monohydrogenmonophosphate dihydrate single crystal samples, abbreviated N ‐DDHP. An assignment of the normal modes is proposed based on group theory analysis and correlations with previous data reported for other homologous hydrogen‐bonded systems. A careful analysis of the vibrational spectra shows that the assignment of the fundamental vibrational modes can be done based on phosphate, organic and water group vibrations. In addition, differential scanning calorimetry measurement and a Raman spectroscopic study at several temperatures in the range 100–300 K are presented. The occurrence of a low‐temperature phase transition near 220 K is well evidenced. From the temperature‐dependence behavior of some internal and external modes, this transition is interpreted by an order–disorder transition which involves the structural modifications of both anion and cation groups. Copyright © 2006 John Wiley & Sons, Ltd.