PULSE-RADIOLYSIS STUDY OF BUCKMINSTERFULLERENE IN BENZENE SOLUTION - ASSIGNMENT OF THE C-60 TRIPLET-TRIPLET ABSORPTION-SPECTRUM

Pulse radiolysis and, to a lesser extent, laser flash photolysis have been used to determine properties of the lowest triplet of C60 in benzene at room temperature, including its absorption spectrum between 300 and 1600 nm, its molar absorption coefficient (epsilon(T)=20200+/-2000 dm3 mol-1 cm-1 at 750 nm) and its quantum yield of formation (PHI(T)=0.88+/-0.15). The features of the triplet spectrum are assigned according to the triplet transition energies based on molecular orbital calculations previously reported; the strong band at 750 nm is attributed to the 2 3G(u)-1 3T2g transition. Implications of the results are discussed, including those related to C60 as an optical limiting material.