7: Further Characterization of Molecular Orbitals
- Page ID
- 60560
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The most elementary molecular orbital models contain symmetry, nodal pattern, and approximate energy information
- 7.1: The LCAO-MO Expansion and the Orbital-Level Schrödinger Equation
- In the simplest picture of chemical bonding, the valence molecular orbitals are constructed as linear combinations of valence atomic orbitals according to the LCAO-MO formula.
- 7.2: Determining the Effective Potential
- In the most elementary models of orbital structure, the quantities that explicitly define the potential V are not computed from first principles as they are in so-called ab initio methods. Rather, either experimental data or results of ab initio calculations are used to determine the parameters in terms of which V is expressed. The resulting empirical or semi-empirical methods discussed below differ in the sophistication.
- 7.3: The Hückel Parameterization
- The Hückel mode is the most simplified orbital-level model. Its implementation requires knowledge of the atomic resonance and exchange values, which are eventually expressed in terms of experimental data, as well as a means of calculating the geometry dependence of the βμ,νβμ,ν 's (e.g., some method for computing overlap matrices Sμ,νSμ,ν ).
- 7.4: The Extended Hückel Method
- It is well known that bonding and antibonding orbitals are formed when a pair of atomic orbitals from neighboring atoms interact. The energy splitting between the bonding and antibonding orbitals depends on the overlap between the pair of atomic orbitals.