Relativistic bond length and atomic orbital contractions

Abstract

Bond lengths and vibrational frequencies for Xe₂ ⁺ and Au₂ were computed using non-relativistic valence-electron wavefunctions with relativistic effective potentials and also using relativistic valence-electron wavefunctions with non-relativistic effective potentials. For both molecules the former gives the relativistic bond length and the latter and non-relativistic bond length. This appears to support the points of view that the relativistic bond length contraction is largely independent of atomic orbital contractions.