As a preliminary step in
the development of a satisfactory molecular-orbital treatment of molecules
incorporating second-row atoms, the VESCF molecular-orbital method is
reconsidered, particularly with respect to evaluation of basic parameters. Appropriate methods of
deriving valence-state ionization potentials, resonance integrals, monocentric and bicentric coulomb
repulsion integrals, and monocentric exchange
integrals are considered. The particular problem of properly treating 3d-orbitals is examined and the use of Burns's rules for
evaluating orbital exponents is suggested. Since the efficacy of the
various procedures depends upon obtaining reliable molecular wave functions, a
brief review is given of the kinds of experimental data that will be used in
Part 11 to test the VESCB wave functions.
Ab initio
electron-phonon interactions using atomic orbital wave functions