Intramolecular distances determined by energy transfer. Dependence on orientational freedom of donor and acceptor



The dependence of Förster long-range resonance energy transfer efficiency on the orientational freedom of donor D and acceptor A molecules attached to a macromolecular substrate is examined. The usefulness of polarized emission measurements in determining the mutual orientation as well as the degree of orientational freedom of D and A and thereby deriving maximum and minimum values for the DA separation from the transfer efficieny is demonstrated.