High‐temperature Raman spectroscopy of monohydrated L ‐asparagine:Cr 3

Raman scattering of L ‐asparagine:Cr 3+ was studied over the complete range of wavenumbers at temperatures from ambient to ∼410 K. A qualitative change in the spectrum occurs when the temperature approaches 400 K. In the region of the spectrum corresponding to lattice vibrations of the crystal some bands disappear, as they do in the intermediate range of wavenumbers 200 cm −1 < ν < 1000 cm −1 , where some new peaks also appear. Similar changes also occur in the highest spectral region, for wavenumbers >3000 cm −1 , which is associated with water molecule vibrations. The changes indicate a modification of the crystal structure with irreversible loss of water molecules during the heating process. Copyright © 2006 John Wiley & Sons, Ltd.