Long-range electron transfer driven by two lasers: Induced irradiance

Kinetics and nonlinear optical properties of a long range electron transfer complex in a polar solvent are studied in the presence of two perpendicularly directed, independent (incoherent) lasers with electric fields aligned along the electron path. The rate constant and absorption/emission cross sections in both direction are computed on the basis of the channel approach, whose validity is justified by a rigorous derivation. It is found that despite strong dissipation due to interaction with the polar environment, emission can be stimulated in one ("primary") direction. The emission spectra are found to depend on the frequency of the auxiliary laser propagating perpendicular to the direction of the primary laser, the intensities of both lasers, the frequency and reorganization energy of quantum modes in the solvent, and the reaction heat. The emission spectrum is only slightly sensitive to the laser intensities in certain high frequency regimes. The latter property is important for potential applications in which the reaction system would be employed as the working system for a laser with tunable frequency. Calculations suggest that a long range electron transfer system can be also used as a nonlinear optical device which transfers energy from one laser to another. (C) 1998 American Institute of Physics.