Attachment of two electrons to C60F48: Coulomb barriers in doubly charged anions

The highly fluorinated chiral C3h molecule C60F48 was observed to sequentially attach two electrons in the gas phase to produce C60F482- and C60F462- + F2. The first electron affinity (EA) of C60F48 was measured to be 4.06 0.3 eV. The first and second EA were calculated to be EA1 = 5.07 eV and EA2 = 2.27 eV for the more symmetric D3d isomer. The dianion was found to be more stable with respect to electron detachment than the singly charged anion. This remarkable stability of the dianion is attributed to a potential barrier resulting from the long range Coulomb repulsion and short range electron-molecule binding.