Recent advances in prethermal chemistry: real-time probing of elementary electron transfer reactions

In liquids and electrolyte solutions, elementary radical reactions may be i nvestigated on the time scale of molecular motions by femtosecond visible-I R absorption spectroscopy. Some studies devoted to the microscopic understa nding of sub-picosecond prehydration electron transfer between an aqueous h alide ion (Cl-) and ionic acceptors (Cd++, H+) are presented. Within an ele ctron hydration regime, the one-electron reduction of a metallic ion or a h ydrated proton (hydronium or dihydronium ion) is totally achieved in less t han 2 x 10(-12) s at 294 K. The consequences of an early partition between reactive and nonreactive IR electronic pathways on the electron hydration p rocess are discussed.