H. L. Tavernier

Photoinduced intermolecular electron transfer in complex liquids: Experiment and theory

Photoinduced intermolecular electron transfer between Rhodamine 3B and N,N-dimethylaniline has been studied in a series of seven liquids: acetonitrile, ethanol, propylene glycol, and mixtures of ethanol, 2-butanol, ethylene glycol, propylene glycol, and glycerol. In each liquid, the donor and acceptors have different diffusion constants and experience distinct dielectric properties. Ps time-dependent fluorescence measurements and steady-state fluorescence yield measurements were made and analyzed using a detailed statistical mechanical theory that includes a distance-dependent Marcus rate constant, diffusion with the hydrodynamic effect, and solvent structure. All solvent-dependent parameters necessary for calculations were measured, including dielectric constants, diffusion constants, and redox potentials, leaving the electronic coupling unknown. Taking the distance-dependence of the coupling to be β=1 A−1, data were fit to a single parameter, the coupling matrix element at contact, J0. The theory is abl...

Photoinduced electron transfer between donors and acceptors on micelle surfaces

Abstract Fluorescence time-dependence and fluorescence yield data are used to examine photoinduced electron transfer between N,N-dimethylaniline and octadecylrhodamine B on the surfaces of dodecyltrimethylammonium bromide (DTAB) and Triton X-100 micelles. The data are analyzed with a detailed theory that includes diffusion of the chromophores over the micelle surface and models the reaction rate by a distance-dependent Marcus form. Good agreement between theory and experiment is obtained for reasonable choices of the transfer parameters for DTAB. However, for Triton X-100, there is reasonable agreement between theory and experiment only for values of the parameters that verge on unphysical. Possible explanations are discussed.

Solute–solute spatial distribution in hydrogen bonding liquids probed with time-dependent intermolecular electron transfer

Solute–solute spatial distribution in strongly hydrogen bonding solvents is investigated using photoinduced electron transfer dynamics between rhodamine 3B (R3B) and N,N-dimethylaniline (DMA) in a series of monoalcohols, polyalcohols, and alcohol mixtures. Fluorescence up-conversion data are presented on electron transfer in ethylene glycol and are compared to data characterizing electron transfer in seven other solvents. The data are analyzed with a detailed statistical mechanical theory that includes a distance-dependent Marcus rate constant, diffusion with the hydrodynamic effect, and solute–solute radial distribution functions. When the standard assumption is made that for low concentration solutes the solute–solute spatial distribution follows that of the solvent’s radial distribution function, a single parameter fit to the electronic coupling matrix element results in the same value, independent of solvent, for data from five solvents. However, it is impossible to fit the data from the solvent ethyl...