Femtosecond pump/probe photoelectron spectroscopy of isolated C60 negative ions

We have measured pump/probe photoelectron spectra of mass-selected, near room temperature C-60(-) in the gas phase. The lifetime of the vibrationally excited (B)over tilda (-)(E-2(g)) state at a calculated energy of 1.26 eV was found to be tau=2.2 +/- 0.2 ps. The dominant decay process corresponds to intramolecular radiationless transitions into ground state C-60(-). This is in contrast to C-60 for which pumping at the absorption onset (1.95 eV) leads to predominantly intersystem crossing. (c) 2006 American Institute of Physics.