FT-EPR study of triplet state C60. Spin dynamics and electron transfer quenching

✍ Scribed by Carlos A. Steren; Patricia R. Levstein; Hans van Willigen; Henry Linschitz; Laszlo Biczok

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 502 KB
• Volume: 204
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(93)85600-s

✦ Synopsis

A Ff-EPR study was made of paramagnetic species formed by pulsed-laser excitation of Cm in fluid solution. Earlier findings that photoexcitation of Cso in fluid solution gives rise to an EPR signal with narrow linewidth were confirmed. The lifetime of the signal corresponds to that of the CGO triplet as measured by flash photolysis. In the presence of donors, the rate of signal decay is increased and matches the growing in of EPR signals from oxidized donors. The time dependence of the FT-EPR spectra gives values for electron transfer rate constants which agree with those derived from flash photolysis measurements on the same systems. Based on these findings, we assign the narrow line signal to the triplet of &,. The time evolution of the FT-EPR signal establishes that the triplets are born with less spin polarization than the thermal equilibrium value. As a result, signal growth is controlled by spin-lattice relaxation.