Laser flash photolysis study of photophysical and photochemical properties of a higher fullerene, C₇₆

Photophysical and photochemical properties of C₇₆ have been investigated by using nano- and picosecond laser flash photolysis methods. In the nanosecond laser flash photolysis of C₇₆, transient absorption ascribable to the triplet excited state of C₇₆ (^TC₇₆*) was observed in the visible and near-IR regions. From the generation of the absorption band of ^TC₇₆*, the lifetime of the singlet excited state was estimated to be 1.7 ns. Under the presence of β-carotene in toluene, ^TC₇₆* was deactivated by energy transfer to β-carotene at a 2.6 × 10⁹ M^-1 s^-1 rate constant. Electron-transfer reaction to ^TC₇₆* was also confirmed in a benzonitrile solution containing C₇₆ and tetramethyl-p-phenylenediamine (TMPD) as an electron donor. A bimolecular rate constant for quenching of ^TC₇₆* by TMPD was estimated to be 7.8 × 10₈ M^-1 s^-1.