Spectroscopic evidence for hydrated electrons in the electrolysis of water

This paper describes the observation and measurement of a strong absorption at 6 330 Å by a species produced very close to a polished silver cathode in the electrolysis of aqueous solutions. The species is likely to be the hydrated electron, thus corroborating some earlier chemical evidence. The technique involves directing a laser beam along a long, curved, polished, silver electrode surface and measuring very small changes in light transmission by modulating the electrolytic current at a frequency to which the detector's amplifier has been tuned.