SPECTROSCOPY AND PHOTOPHYSICS OF C60H18 AND C60H36

Ground and triplet state spectroscopic and photophysical properties of C60H18 and C60H36 have been studied using the complementary technique s of nanosecond pulse radiolysis and laser flash photolysis to determi ne triplet-triplet (T-T) absorption spectra, triplet lifetimes, T-T mo lar absorption coefficients and triplet quantum yields, in particular for C60H18. The spectroscopic and photophysical properties of C60H18 a re similar to those of an sp(2) network species such as C-60, whereas those of C60H36 resemble benzene. No T-T absorption was observed for C 60H36 at lambda > 300 nm, so that its triplet state parameters could n ot be measured. The most probable assignment of the C60H36 samples stu died, on the basis of vibrational and electronic spectra and structure , is to an S-6 symmetry isomer, but the lowest energy T and D-3d isome rs are not entirely excluded, Our partially hydrogenated fullerene sam ples were prepared by a transfer hydrogenation method. Other preparati on techniques may have produced other isomers of these species, thus a ccounting for some differences in reported spectroscopic results.