Prediction of Interatomic Distances and Force Constants in Diatomic Hydrides

The interatomic distance in hydrides is roughly the radius in the united atom at which Zeff=1.0. The force constant is roughly 4πρe2 where ρ is the electron density at this radius. These results are justified by a perturbation treatment. The best fit to experimental values is obtained using Hartree wave functions. Slater functions account for the general trends and breaks in the curves of distance and force constant vs. atomic number, and for the anomalous values noted by the Sheline in the transition elements.