Ionization potentials and bond lengths for CO, N₂, and F₂ using the SCF-Xα-SW method: A study of the effect of overlapping spheres

Abstract

Using a simple, arbitrary, but fixed procedure for the choice of sphere sizes in the overlapping sphere version of the SCF-Xα-SW method, results for the ionization potentials of CO, N₂, F₂, and H₂O are in considerably better agreement with experiment than those of the muffin-tin version. The agreement is as good as those of the SCF-Hartree-Fock, Discrete Variational-Xα, and LCAO-Xα methods. For the first time the overlapping sphere modification has been used to calculate binding curves and results in equilibrium bond lengths for CO, N₂, and F₂ all within 0·3 a ₀ (0·16 Å) of the experimental values, a dramatic improvement over the muffin-tin results. The variation of the calculated ionization potentials under a moderate change in the amount of sphere overlap is found to be rather small, being of the order of the differences between the DV-Xα and LCAO-Xα methods, both of which completely avoid the muffin-tin approximation.

Additional information

Notes on contributors

R.P. Messmer

Visiting Scientist, Department of Materials Science and Engineering, Massachusetts Institute of Technology.

K.H. Johnson

Research sponsored by the National Science Foundation and the Petroleum Research Fund (administered by The American Chemical Society).