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Raman and Neutron Scattering Study of Partially Deuterated L ‐Alanine: Evidence of a Solid‐Solid Phase Transition
Author(s) -
de Souza Joelma M.,
Freire Paulo T. C.,
Argyriou Dimitri N.,
Stride John A.,
Barthès Mariette,
Kalceff Walter,
Bordallo Heloisa N.
Publication year - 2009
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200900482
Subject(s) - raman spectroscopy , deuterium , neutron diffraction , inelastic neutron scattering , chemistry , raman scattering , crystallography , neutron scattering , inelastic scattering , kinetic isotope effect , neutron , hydrogen bond , phase transition , analytical chemistry (journal) , nuclear magnetic resonance , crystal structure , scattering , atomic physics , molecule , condensed matter physics , organic chemistry , physics , optics , quantum mechanics
Raman and neutron experiments using specific isotope labeling were combined in order to study the dynamics and structure of L ‐alanine. Inelastic neutron and Raman scattering data of C 2 H 4 (ND 2 )CO 2 D are discussed in relation to the doubling of the lattice parameter a observed by means of neutron powder diffraction in C 2 D 4 (NH 2 )CO 2 H. The major changes accompanying the phase transition are found in the vibrational frequencies involving the torsional vibration τ (CO 2 − ), which is clearly affected by the hydrogen bonds between the protons of the ammonium group and the oxygen atoms of the carboxylate group. At lower temperatures the rearrangement of identifiable hydrogen bonds induces changes in the bending vibration δ (ND 3 ), confirming some orientational disorder.