Theoretical Bits

Raman Spectroscopy

The Raman effect was discovered simultaneously by Raman and Krishnan1, and by Landsberg and Mandelstam2 in 1928. It was Raman, however, who was awarded with a Nobel prize in 1930 for its discovery.     The effect consists in the shift in frequency of a small fraction of the light scattered by a sample. This […]

Photoluminescence

Luminescence is electromagnetic radiation (light) emitted from a material in a non-equilibrium state. That is, radiation different than the one emitted by a black body in thermodynamic equilibrium according to Planck’s law1.   In order to bring the system out of equilibrium, it is necessary to apply an external excitation energy to it. This energy […]