THE EFFECT OF A LASER FIELD ON ELECTRON-TRANSFER IN METAL-COMPLEXES -QUANTUM DEGREES OF FREEDOM

The effect of a strong cw laser field on Fe(OH2)(6)(+3) electron trans fer in aqueous solution is considered. On the basis of a kinetic maste r equation for the time-dependent population, an analytical solution f or the forward and backward reaction rates is obtained. The presence o f a strong ion-ligand vibration at HBAR omega(q) = 432cm(-1) qualitati vely changes the intensity dependence of the sum of forward and backwa rd rate constants (denoted as the ''total rate constant''). It is show n that the total rate constant is strongly dependent on the laser freq uency. For the symmetric exchange reaction this rate constant exhibits resonances as a function of the cw field amplitude. For the activatio nless reaction (achievable by application of an additional de field) i t decreases sharply with the cw field intensity. It is shown that the asymptotic populations of the reactant and product states are non-Bolt zmann; their ratio can be varied by 18 orders of magnitude. Contrary t o the case with no ac field, the equilibrium constant exhibits a nonmo notonic dependence on the reaction heat, epsilon. In some regions of e psilon it is insensitive to the reaction heat. The analytical solution is verified via numerical solution of the original master equation. E xcellent agreement is obtained. (C) 1995 American institute of Physics .