The structures of c-C4F8 and c-C4F8- and the adiabatic electron affinity of c-C4F8

Calculations at the 6311G(dps) level have been used to elucidate the structures of octafluorocyclobutane c-C4F8 and its negative ion c-C4F8-. With no empirical adjustments, we obtain 0.640 eV for the adiabatic electron affinity of c-C4F8. This may be compared with an experimental value of 0.63 +/- 0.05 eV from the FALP method. c-C4F8 has unusual features in that there is an increase in symmetry, D-2d to D-4h, in going from the neutral molecule to the negative ion, and the singly occupied molecular orbital in the ion has an unexpected nodal structure. (C) 2004 Elsevier B.V. All rights reserved.