Interpretation of intramolecular energy transfer experiments

The measurement of the efficiency of resonance energy transfer between two luminophores attached to the same macromolecular substrate is a promising tool for determining intramolecular distances if reasonable bounds can be placed upon the orientation factor k2, To date, the analysis of such experiments has been based upon assumed average values of k2. A critical review of this procedure is offered along with a method for estimating upper and lower limits for k2 which derive from the freedom of motion of the luminophores as determined by polarized emission spectroscopy.