Article,
High pressure Raman scattering of DL-leucine crystals
VIBRATIONAL SPECTROSCOPY, (2013)
DOI: 10.1016/j.vibspec.2013.03.001
Abstract
We have obtained the Raman spectra of DL-leucine crystal through a
diamond anvil cell for pressures between 0 and 5 GPa. The observation of
several anomalies in the regions of both the lattice mode and the
internal mode suggests that the crystal undergoes a phase transition
between 2.4 and 3.2 GPa. This phase transition is preceded by a gradual
change of the molecular conformation of leucine molecules in the unit
cell. We show that, up to 5 GPa, the DL-leucine crystal is more stable
than the chiral L-leucine crystal because while the former presents only
one phase transition in the 2.4-3.2 GPa interval, the latter presents
three different transitions, the first of which is observed at 0.46 GPa.
Additionally, when pressure is released to 0.0 GPa, the original Raman
spectrum is recovered, indicating that the modification at high pressure
on DL-leucine crystal is reversible. (C) 2013 Elsevier B.V. All rights
reserved.
