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.