The dissociation energies of FeF, FeCl, and FeBr and their positive ions

Accurate dissociation energies are computed for FeF, FeCl, and FeBr and their positive ions using the coupled cluster approach in a large basis set and a correction based on CuCl, where then are accurate experimental results for comparison. While the computed IP for FeCl agrees with the recent experimental appearance potential, our best estimate for D-0 is significantly larger then the recent experimental determination. Our best estimates for the D, values of FeF, FeCl, and FeBr are 4.91 +/- 0.14, 3.73 +/- 0.14 eV, and 3.09 +/- 0.21 eV, respectively, and 4.51 +/- 0.14, 3.51 +/- 0.14, and 2.72 +/- 0.21 eV for the positive ions. The results obtained using B3LYP functional are in reasonable agreement with those obtained at higher levels of theory.