Accession Number : AD0739141

Title :   Photoexcitation of Hydrated Electrons Using a Q-Switched Ruby Laser,

Corporate Author : BRITISH COLUMBIA UNIV VANCOUVER DEPT OF CHEMISTRY

Personal Author(s) : Kenney-Wallace,Geraldine ; Walker,David C.

Report Date : 15 FEB 1971

Pagination or Media Count : 5

Abstract : The lifetime of the photoexcited state of the hydrated electron in liquid water at room temperature is shown to be less than 6 x 10 to the -12 sec following photoexcitation at 694 nm, a wavelength very close to lambda(max). This has implications concerning the nature of the optical transition involved and may suggest that the absorption band is a photoionisation efficiency profile rather than an electronic transition to a bound excited state. The absorbance of hydrated electrons (produced by uv flash photolysis) was measured at very high light fluxes using a Q-switched ruby laser under conditions where cryptocyanine and methylene blue solutions showed marked nonlinear absorption due to saturation of optical transitions. Whereas the dye solutions showed diminished absorbance and a shortening of the laser pulse at high light intensities, hydrated electrons gave identical absorbance at all intensities, varied over 7 orders of magnitude, up to 200 photons per hydrated electron per sq cm of the light beam. (Author)

Descriptors :   (*ELECTRONS, PHOTON BOMBARDMENT), (*SOLUTIONS(MIXTURES), ELECTRONS), HYDRATES, LASERS, EXCITATION, RELAXATION TIME, ELECTRON TRANSITIONS

Subject Categories : Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE