Decay of hollow atoms inNe10+−C60collisions

Abstract

We have studied the decay of hollow atoms formed in ${\text{Ne}}^{10+}{\text{\ensuremath{-}}\mathrm{C}}_{60}$ collisions at low energy $(E=100\phantom{\rule{0.3em}{0ex}}\text{keV})$. The decay products of hollow atoms, i.e., the scattered projectiles and the number of ejected electrons from autoionization cascades, have been measured. The projectile energy loss has been analyzed as a function of the final charge state, in order to differentiate collisions at large distance, near the ${\mathrm{C}}_{60}$ through the electronic clouds and inside the ${\mathrm{C}}_{60}$ cage. For scattered projectiles ${\text{Ne}}^{8+}$ where two electrons are stabilized $(s=2)$, up to 16 ejected electrons have been observed, and lower energy loss compared to projectiles with more stabilized electrons $(sg2)$ has been measured. These results are interpreted by the formation and relaxation of completely neutralized compact hollow atoms passing very close to the ${\mathrm{C}}_{60}$ molecule (into the electron clouds). The observed large number of ejected electrons is explained by a direct filling of the $N$ shell during the interaction time and a fast decay via quasicomplete autoionization cascades.