2. Material and method

2.1 Description of the Raman effect

The Raman effect was discovered in 1928 by the Indian physicist Chandrashekhara Venkata Râman. It results from the interaction of photons from a monochromatic light source with sample molecules. When the photons are elastically scattered by the molecules, i.e. without any change in energy, this scattering is called "Rayleigh scattering". When photons are scattered inelastically with a change in energy, this is called "Raman scattering". The wavelength shift corresponds to a vibrational transition and, unlike fluorescence, does not depend on the excitation wavelength. The unit used is a relative unit given in cm ^–1 . The Raman spectrum provides a fingerprint of all the bonds present in the material under...