CHARGE TRANSFER PROCESSES IN ELECTRON-DONOR-ACCEPTOR COMPLEXES IN SOLIDS AT LOW TEMPERATURE.
Technical rept., 1 Dec 65-31 Jan 67,
CALIFORNIA UNIV SANTA BARBARA
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The charge transfer spectra of several donor-acceptor pairs have been studied at low temperatures by vapor deposition for the benzene-iodine complex and by polymer matrix isolation techniques for other aromatic hhydrocarbons complexed with tetrachlorophthalic anhydride and trinitrofluorenone. The spectra obtained from benzene and iodine sprayed on a cold window showed the characteristic charge transfer absorption band of benzene and iodine centered at about 300 A and approximately 300 A wide. The molecular complexes isolated in polymer matrices were studied at 298 K and 77 K by absorption, luminescence, and excitation spectroscopy. Lowering the temperature increases the intensity of absorption and of luminescence by reducing quenching, but has insignificant effect on the spectral location of the charge transfer band maximum in absorption and fluorescence. Hence the Stokes shift for the charge transfer process is unaffected over this temperature range. The occurrence of charge transfer fluorescence for a series of donors complexed to the same acceptor is sensitively dependent upon the location of the donor triplet state. The charge transfer interaction enhances the population of the donor triplet state. The excitation spectra show structure and splitting in the charge transfer band. Author
- Nuclear Physics and Elementary Particle Physics