Time-resolved EPR study of C-3(60) in solid matrices

Using time-resolved cw EPR and pulsed EPR techniques, a study was made of the characteristics of the photoexcited triplet state of C-60 adsorbed in silica gel pores and embedded in a polymethylmethacrylate matrix. It was found that the time-resolved spectra from C-3(60) in these matrices at room temperature retain the absorption/emission features of spectra from C-3(60) in frozen solution (less than or equal to 120 K). Apparently, the combination of molecular rotation and pseudo rotation (resulting from interconversion between Jahn-Teller states) is not fast enough to lead to complete averaging of the dipole-dipole interaction between the unpaired electrons. The study explored the effect of introduction of solvent molecules in the silica gel pores on the C-3(60) spectrum and quenching of the triplet by electron donors.