Split-Shell Molecular Orbitals for Sigma-Bonded Systems: Hydrogen Halides

Abstract

A split‐shell molecular orbital calculation has been made for the pair of bonding electrons in the molecules HF, HCl, HBr, HI. The results compare favorably with an earlier closed‐shell calculation by Pohl, Rein, and Appel, and in particular cause the interatomic potential to have the correct limiting behavior at large distances. It is shown that, even using real atomic orbitals, the coefficients in the optimum split‐shell molecular orbitals may be complex, in which case the two split‐shell orbitals are complex conjugates, describing the same spatial distribution but with different relative phases.