Polarization of the Fluorescence of Solutions Subjected to an Electric Field

Abstract

The dipole moments of fluorescent molecules in nonpolar solvents in the lowest singlet excited state has been previously calculated from observations of the increase in fluorescence polarization when the molecules are subjected to an electric field on the assumption that the Langevin distribution prevails at the time of the emission. By the use of Benoit's theory of the rotational diffusion of a dipole placed in an electric field, and under conditions of isotropic depolarization, an equation is obtained which allows the calculation of the excited dipole moment when the equilibrium distribution is not reached during the excited state.