We report on the measurement of double-differential distribution of soft electron emission from C60 fullerene, induced by a fast-moving Coulomb field of 76 MeV energy bare fluorine ions. A broad "plasmon-electron" peak, riding on the Coulomb-ionization continuum, is observed due to the deexcitation of the giant dipole plasmon resonance state in C60. The angular distribution of the plasmon electrons goes through a dip around 90, which is contrary to that observed in ion-atom collisions measured in situ, indicating the alignment of the induced dipole moment along the projectile beam direction. A model based on the photoelectron angular distribution which is modified due to the ion-induced postcollisional interaction provides an excellent agreement with the observed asymmetric distribution. The distribution smoothly changes from a dip at 90 to a peak with the variation of ejected electron energy indicating transition from a collective plasmon behavior of the whole system to a single ion-atom interaction. The single-differential cross section was also derived, which preserves the signature of the collective excitation.
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|Publication status||Published - Nov 18 2015|
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics