All-Electron Hybrid Density Functional Calculations on UF_n and UCl_n (n = 1−6)

We calculate the bond dissociation energies of the series UF_n and UCl_n (n = 1−6) using the all-electron third-order Douglas-Kroll-Hess approximation in combination with hybrid density functionals. The spin−orbit (SO) operator is included self-consistently using the nuclear-only SO and the screened-nuclear SO approximations. Results are in very good agreement with experimental values, with the exception of the smallest molecules of each series, UF and UCl. By shifting the one-electron orbital energies of UF₆ and UCl₆ to match the HOMO level with the ΔSCF calculated value of the first ionization energy, we are able to reproduce the main features of the photoelectron spectrum of these two molecules.