Open AccessLong-Range Electron Tunneling in Aqueous and Organic Glasses
Author(s) -
Oliver S. Wenger,
Harry B. Gray,
Jay R. Winkler
Publication year - 2005
Publication title -
chimia
Language(s) - English
Resource type - Journals
eISSN - 2673-2424
pISSN - 0009-4293
DOI - 10.2533/000942905777676786
Subject(s) - quantum tunnelling , electron transfer , range (aeronautics) , electron , van der waals force , quenching (fluorescence) , chemical physics , luminescence , toluene , chemistry , aqueous solution , atomic physics , molecular physics , condensed matter physics , photochemistry , materials science , physics , fluorescence , molecule , optics , optoelectronics , nuclear physics , organic chemistry , composite material
Photoinduced electron transfer (ET) reactions have been investigated in glassy media at 77 K. Distance decay parameters for electron tunneling through water, 2-methyltetrahydrofuran, and toluene have been determined through measurements of donor luminescence quenching by randomly dispersed electron acceptors. Remarkably different long-range ET efficiencies in the three solvents are in accord with the predictions of a super exchange model of distant electronic couplings. We conclude that tunneling energy effects play an important role in long-range ET reactions, and further that the coupling drops off very rapidly across van der Waals gaps betwee nmolecules in glasses.