Application of the Equivalent Bond Orbital Model to the C2s-Ionization Energies of Saturated Hydrocarbons

✍ Scribed by Gerhard Bieri; James D. Dill; Edgar Heilbronner; Andreas Schmelzer

• Publisher: John Wiley and Sons
• Year: 1977
• Tongue: German
• Weight: 762 KB
• Volume: 60
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19770600715

✦ Synopsis

It is shown that the ab znitio STO-3G treatment applied to simple saturated linear, branched and cyclic hydrocarbons, assuming standard geometries, yields orbital energies e p -3 G for their canonical orbitals yl which correlate perfectly with the observed C2, ionization energies If", if Koopmuns' approximation is accepted.

Applying the Foster-Boys localization procedure to these canonical orbitals yJ leads to localized orbitals Ap and their corresponding Hartree-Fock matrix FA=(FAJ. An examination of the matrix elements F, 1,, . z.e. of the self-energies A,= F, ,~L of the localized CC-and CH-orbitals 1, and of the cross terms F,,pv (p # v) 1. Introduction. -In a series of classical papers Lennard-Jones & Hall 111 introduced into molecular orbital theory the concept of 'equivalent orbitals' (EO), e.g. orbitals xxy localized between two bonded atoms x, y of a hydrocarbon. The EO's xxy form the basis for an LCBO description of the delocalized molecular orbitals (LCBO = Linear Combination of (equivalent) Bond Orbitals). The relevant matrix elements with respect to a defined hamiltonian P a r e the self-energies HXY,XY= A,, of