The FTIR and FT Raman spectra of natural, deuterated, and N-15 substituted
crystals were recorded and interpreted. The FTIR spectra were studied down
to a temperature of 90 K. DSC measurements were carried out in the temperat
ure range 95-425 K. No phase transition was found in this temperature range
by DSC and FTIR. (C) 1999 Elsevier Science B.V. All rights reserved.