Optical centers, interaction with energy transfer

In this section we will first consider the configurational coordinate diagram 4,7) that describes the interaction of an optical center with its surroundings in the absence of center-center interaction. Later we will deal with the interaction between two centers that results in energy transfer (4,8). 

The above described methodologies have allowed us to conduct spectroscopic studies with a finesse which is not easily attainable using conventional techniques. These laser based techniques in some combination or variation have provided us with the means to resolve or to deconvolute intrinsic features connected with the energy level structure of the systems of interest. These features have so far been assumed to remain static as a function of time. This is, of course, not always the case as various interactions of centers with their environs produce dynamical changes in the excited state and lead to relaxation, optical energy dissipation and transfer. These processes are not generally radiative. 

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