Pump-Probe Spectroscopy of the Hydrated Electron in Reverse Micelles

Abstract

Ultrafast spectroscopy was used to investigate the excited state dynamics and photochemistry of the hydrated electron in the water pool of a reverse micelle (RM) comprised of water and the surfactant, AOT, dissolved in an isooctane solution. Solvated electrons were generated in the isooctane solvent by photoionization (three photons of 400 nm). The isooctane-solvated electrons were observed to rapidly attach to the RM and relax in the water pool within 1 ps. A second 400 nm excitation pulse was employed to excite the equilibrated hydrated electron in the RM water pool, inducing an electron transfer reaction with the surfactant molecules. The ultrafast data as a function of RM size offer new insights on spatial confinement effects on the chemistry and relaxation dynamics of excess electrons in nanometer-sized water pools.