Reliable electron affinities of perfluorocyclopropane and perfluorocyclobutane from convergent ab initio computations

To resolve discrepancies concerning the magnitude of the electron affinities of perfluorocyclopropane and perfluorocyclobutane, quantum chemical calculations have been carried out with the MP2 and CCSD(T) methods in conjunction with augmented correlation consistent basis sets (aug-cc-pVX Z, X = D, T, Q). Though no experimental values have been found for perfluorocyclopropane, we estimate its electron affinity to be 0.17 eV (0.00 eV without zero-point vibrational energy corrections). In addition, determination of the electron affinity of perfluorocyclobutane (0.61 and 0.44 eV with and without zero-point vibrational energy corrections, respectively) is in good agreement with experimental values reported by Miller and co-workers (0.63 +/- 0.05 eV). This study also demonstrates that the widely prescribed B3LYP/DZP++ model chemistry for computing electron affinities does not correctly describe these systems.