The infrared spectra were recorded at room
temperature on a Galactic ABB FTIR spectrometer equipped with an
MCT cryogenic detector, with the sample compartment modified
to accommodate the cryogenic head; 128 acquisitions (recorded
at 4 cm−1 resolution) were typically averaged for each spectrum.
Raman measurements were performed using home-made equipment
consisting of a iHR 320 Symphony-Jobin Yvon spectrometer
containing a CCD detector (cooled by liquid N2) and a laser beam
HeNe (632.8 nm, 10 mW, 2–3 m of diameter, back reflection
geometry); a Super Notch filter has been used in order to eliminate
the Rayleigh scattering.