Picosecond Laser Studies of Electron Solvation in Alcohols

When low-energy excess electrons are UIJeCted. tnto a polar fhud [ I,?] , they become raprdly thermahzed. These thermahzed electrons are butrally locahzed m shallow potentral wells formed by the surroundmg solvent molecules. They are called trapped electrons, et, and are charactertzed by absorption spectra with ma+ ma in the mfrared, a narrow ESR hne, and a sudden drop m mobihty. In the absence of a reactive chemrcal channel, the surrounding solvent dipoles reorrent themselves about the electron, deepening the potentral well and leading to the formatron of the solvated electron, e;. Sohated electrons are characterized by absorptron spectra with maxima m the vrsrble and a broadened ESR hne. The absorption spectral changes takmg place durmg the solvatron process have been followed experlmentally by pulse radrolysrs [3--5]It was fist observed [3] m cold alcohols that an mittal 1R absorption gradually shlfted mto the characterrstic visrble e; absorption band. Subsequent room-temperature prcosecond pulseradrolysrs data [4,5] shows that the decay of the trapped electron at 1300 nm correlates wrth the growth of the solvated electron at 600 nm. The solvatlon rate decreases as the alcohol vrscostty mcreases since the molecular matrons mvolved m the solvatron process slow down. In thus commumcatron we report prehminary results