Recollision during the High Laser Intensity Ionization ofC60

Abstract

Through ${\mathrm{C}}_{60}$, we address the role of electron recollision in the nonresonant, femtosecond laser ionization of large, highly polarizable molecules. We show how the electron trajectories are influenced by the laser field, the laser induced dipole field, and the Coulomb field of the ion core. Working at long wavelengths we observe recollision in ${\mathrm{C}}_{60}$ through the ellipticity dependence of the fragmentation it produces. The ionizing electron emerges from $\mathrm{C}_{60}{}^{z+}$ ($z=3,4$) with a lateral velocity of $\sim 12Å/\mathrm{f}\mathrm{s}$, approximately half its Fermi velocity. Despite the large lateral velocity and competing forces on the electron, recollision remains relatively probable for this scale of molecule.