Nanosecond nonlinear absorption and refraction in C/sub 60//toluene solution

Nonlinear absorption and refraction in C/sub 60//toluene are investigated using the Z-scan technique with trains of picosecond laser pulses extending over /spl sim/70 nanoseconds. Analysis of the experimental results, with a five-energy-band model, assures the contributions of the triplet-triplet excitation and the thermal effect induced by nonradiative relaxation, in addition to the singlet-singlet excitation that was verified in our previous picosecond study.