Relativistic all-electron Dirac–Fock calculations on RnF 6 and its ions

Abstract

Ab initio relativistic all-electron Dirac–Fock (DF) and nonrelativistic (NR) Hartree–Fock (HF) limit self-consistent field (SCF) molecular calculations are reported for the octahedral ( O h ) RnF 6 at various Rn–F bond distances. Our DF and HF calculations predict for the octahedral ( O h ) RnF 6 the bond distance of 2.01 and 2.05 Å, respectively. Both our NR HF and DF SCF calculations predict RnF 6 ( O h ) to be unbound, due to the neglect of electron correlation effects in our calculations. DF and NR HF calculations were also performed for RnF 6 + and RnF 6 −. Electron affinity of RnF 6 calculated with our DF (HF) SCF wavefunction is 5.2 eV (2.86 eV). Relativistic treatment predicts a much larger (∼80%) electron affinity for RnF 6 as compared to the corresponding NR HF calculations. Ionization potential calculated with our DF and HF wavefunctions for RnF 6 ( O h ) is 13.6 and 11.9 eV, respectively. The calculated NR HF HOMO–LUMO gap is 10.76 eV, which is in close agreement with the gap of 10.35 eV obtained from the corresponding DF relativistic MOs (RMO) for RnF 6 ( O h ).