Relaxation of C60 in solutions and films: results of femtosecond measurements
Chekalin S. V. , Farztdinov V. M., Akesson E. , Sundstrom V.
Femtosecond laser spectroscopy has revealed a substantial difference between the relaxation properties of C60 in solutions and in films at excitation intensities 1010-10n W/cm2. An absorption increase with a time scale of 1.2 ps is observed in the solution. This increase is attributed to a restructuring of the molecule after the absorption of a photon. In the film, the induced absorption undergoes a nonexponential decay, at a rate which increases with increasing excitation intensity. This effect is attributed to singlet-singlet annihilation.