ENERGY-GAP DEPENDENCE OF THE CHARGE RECOMBINATION PROCESS OF ION-PAIRS PRODUCED BY EXCITATION OF 2,6,9,10-TETRACYANOANTHRACENE METHYL-SUBSTITUTED BENZENE CHARGE-TRANSFER COMPLEXES IN ACETONITRILE

Charge recombination rates (kCIPCR of contact ion pairs (CIP) formed by the excitation of 2,6,9,10-tetracyanoanthracene (TCA)-methylsubstituted benzene (MB) charge transfer complexes in acetonitrile solution have been measured by directly observing the time-resolved spectra absorption spectra of CIP with picosecond laser spectroscopy; their dependence on the energy gap between the ion pait and ground state has been examined. The energy gap dependence of the kCIPCR of the TCA-MB system has been confirmed to be similar to the pyromellitic dianhydride-MB system, indicating a difference from the usual bell-shape. © 1990.