Abstract
Single-crystal samples of mono-L-alaninium nitrate, known for its
non-linear optical properties, have been studied by Raman spectroscopy
in a diamond-anvil cell up to pressures of 7.4 GPa. The data acquired in
this study are consistent with the hypothesis that a phase transition
takes place between 3.5 and 4.1 GPa, as suggested by the change of Raman
profile in both the low wavenumber and the internal modes spectral
regions. A detailed analysis of the vibrational properties in the
wavenumber region below 130 cm(-1) including the dependence of the
wavenumber of the observed modes as a function of pressure as well a
comparison with previous papers reporting the Raman spectra of the
L-alanine is presented. Correlation between hydrogen bond at room
pressure and the occurrence of the phase transition with pressure
variation was proposed giving new insights about the problem. Upon
decompression to ambient pressure the original spectra were recovered
indicating that the phase transition is reversible.
Users
Please
log in to take part in the discussion (add own reviews or comments).