He capture by negatively charged Buckminsterfullerene

The first observation of capture of He atoms by negatively charged Buckminsterfullerene (C60) is reported. The collision energy dependence of the production of the endohedral complex is presented in the region of the energetic threshold and compared directly with results obtained using positively charged C60. The threshold for capture by negative ions is shifted by ∼ 1.5 eV to higher energies. This shift can be accounted for by considering the different internal energies of the positive and negative ions. (orig.)