Ionization energy of CF3 deduced from photoionization of jet-cooled CF3Br

The ionization energy of CF3+ is investigated by synchrotron radiation phot oionization experiments using a skimmed molecular beam of CF3Br. Care is ta ken to eliminate contributions from higher energy second-order radiation fr om the monochromator gratings and to characterize the molecular beam. From the corrected 0 K CF3+ appearance energy of 12.07 +/- 0.02 eV, we calculate the adiabatic CF3 ionization energy to be 9.04 +/- 0.04 eV, a value in exc ellent agreement with recent calculations and a number of experiments. Appa rent discrepancies with other, significantly lower, determinations of the i onization potential are discussed and explained - particularly those arisin g from a previous CF3Br molecular beam experiment - confirming a recently p roclaimed consensus favoring a value as obtained here.