DYNAMICS OF PHOTOEXCITED DONOR-ACCEPTOR COMPLEXES BETWEEN C-60 AND N,N-DIETHYLANILINE - POLARIZATION PICOSECOND SPECTROSCOPY STUDY

The kinetics of the formation and decay of photoexcited radical ion pa irs of donor-acceptor charge-transfer complexes between C-60 and N,N-d iethylaniline (DEA) in chlorobenzene was studied by picosecond laser-i nduced diffraction gratings. It was established that the anisotropy of polarization of the diffraction signal decreases as the concentration of DEA increases. The radical ion states of the photoexcited C-60(-). ..DEA(+) complex have zero anisotropy. This effect is likely due to th e isotropic intracomplex transfer of an electron from the local excite d state to the radical ion state. The rate constant of quenching of th e singlet excited C-60 by N,N-diethylaniline (1.4.10(10) L mol(-1) s(- 1)) and the lifetimes of the solvent-separated C-60(-)...DEA(+) and ti ght [C-60(-)...DEA(+)] (95 +/- 7 and 31 +/- 4 ps, respectively) radica l ion pairs were measured.