Resonance Raman Spectra of Model Metallo Porphins

The discovery of the laser and its subsequent use as an irradiating source in Raman spectroscopy made it possible to investigate routinely highly-coloured gases1, doped crystals2, 1iquids3,4,5 and solids5. In many cases, however, the incident light has a wavelength which lies within or near the contour of the electronic absorption band. Under such conditions the light is strongly absorbed with rapid heating of the sample which now refracts and diffuses the light into a cone. All the useful features of the laser irradiation are now destroyed and one is surrounded by the well known difficulties associated with scattering from a Hg arc lamp4.