Electronic interactions and interchromophore excitation transfer

Abstract

The nature and variation of the electronic interactions which promote the transfer of singlet electronic excitation between two chromophores are elucidated using a simple four-electron model as a foundation. Two important distance regimes for excited-state intermolecular interactions can be distinguished: short range (ca. 3-6 Å) and intermediate range (ca. 6-20 Å). A unifying model is presented which accounts for both interchromophore orbital overlap effects, which dominate at short-range (using a variational treatment) and intermediate-range interactions (by a quantum electrodynamical description). It is shown that penetration as well as exchange effects are important at close separations. ..