Accession Number:

AD0739141

Title:

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

Descriptive Note:

Corporate Author:

BRITISH COLUMBIA UNIV VANCOUVER DEPT OF CHEMISTRY

Report Date:

1971-02-15

Pagination or Media Count:

5.0

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 lambdamax. 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

Subject Categories:

  • Physical Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE