Experiment nr. 7

Optical spectroscopy at colour centres and molecules

Supervisor:  Dr. Volker Riede

The common physical property of colour centers and the iodine molecule (which will be investigated in this experiment) is the interaction between electronic transitions and vibrations of the atoms. Therefore the Franck-Condon principle holds for both. The position of the absorption maxima of the measured iodine vapour spectrum have to be determined, and from that the convergence energy, the dissociation energy, and the energy of the electronic transition are to be estimated. The colour centers are generated in NaCl-,KCl-, and KBr-crystals by UV- radiation or X-rays. The absorption spectra provide the concentration of the centers in dependence on time, the energy of the electronic transition and the line width. The results have to be compared to values calculated with a classical and a quantum mechanical model.