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High‐pressure Raman spectra of deuterated L ‐alanine crystal
Author(s) -
Gonçalves R. O.,
Freire P. T. C.,
Bordallo H. N.,
Lima J. A.,
Melo F. E. A.,
Filho J. Mendes,
Argyriou D. N.,
Lima R. J. C.
Publication year - 2009
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.2209
Subject(s) - raman spectroscopy , deuterium , chemistry , diffraction , molecule , alanine , phase transition , spectral line , crystal (programming language) , crystallography , wavenumber , analytical chemistry (journal) , optics , physics , atomic physics , organic chemistry , thermodynamics , amino acid , biochemistry , astronomy , computer science , programming language
Raman spectra of deuterated L ‐alanine have been obtained at high‐pressure conditions. A phase transition at ∼1.5 GPa associated with the splitting of some internal modes and increase of the wavenumber of the external modes was observed. Similarly to the hydrogenated L ‐alanine crystal, this first transition was related to a symmetry change. Moreover, further modifications of the Raman spectra were observed at 4.4 GPa, which may be associated to conformational changes of the molecule. To give further support to such a hypothesis, neutron powder diffraction measurements were performed. Information about the cell parameter at atmospheric pressure gave valuable information about the ND distances, shedding light on the behavior of the torsional vibration of ND 3 + . Copyright © 2009 John Wiley & Sons, Ltd.