Harumichi Kobashi

Influence of triplet—triplet excitation transfer on the decay function of donor luminescence

Abstract The triplet—triplet electronic excitation transfer from benzophenone to naphthalene in rigid solutions has been investigated by measuring the non-exponential decay curve of benzophenone photphorescence using a laser pulse for excitation. The results of measurements were satisfactorily reproduced by Inokuti—Hirayamas formula based on Dexters theory of exchange interaction.

Hydrogen atom abstraction by p-chloranil triplet from tetrachlorohydroquinone and the presence of a competitive deactivation process

Efficiencies of the formation of p-chloranil semiquinone radicals from p-chloranil triplet were determined in the p-chloranil—tetrachlorohydroquinone systems by laser flash spectroscopy. The hydrogen abstraction occurs depending on solvent polarity and competes with another deactivation process. This result suggests the existence of the triplet exciplex as an intermediate.

Ion-pair formation competing with internal conversion from the second excited state in the chloranil-diphenylamine complex

Abstract Excitation-wavelength dependence of relaxation in the chloranil (CA)-diphenylamine (DPA) complex was studied by means of laser photolysis. The photolysis at the first charge-transfer (CT) band showed ultrafast relaxation to the ground state, while the excitation at the second CT absorption band led to the formation of a short-lived (≈40 ps) ion pair prior to growth of a triplet ion pair with a lifetime of ≈ 7 ns.