Energy transfer in a static electric field

The issue of how the application of a static electric field can influence energy transfer between molecules is addressed. Several aspects are considered. First, in molecules of reasonably high symmetry where the donor decay or the acceptor excitation transition is electric dipole forbidden, the application of a static field can, by an electro-optical interaction, allow energy to transfer by a dipolar mechanism. In this way application of the field effectively switches on the transfer process. Secondly, it is shown how the application of a static electric field can provide more spectroscopic information, as in the technique of electric field-induced spectroscopy: it also offers a possible basis for new types of laser system. Finally, in a polar liquid an applied field can produce a degree of molecular alignment. It is demonstrated how this can significantly modify energy transfer characteristics, and the dependence of the effect on field strength and temperature are identified.