Molecular Orbital Tutorial

Molecular Orbital Tutorial
Barry Linkletter
Department of Chemistry, University of Prince Edward Island
Abstract
This tutorial examines a method for constructing hybrid orbitals. Combinations of
atomic orbitals are referenced to the bonds of tetrahedral, trigonal planar and linear
carbon centres to create the famous hybrid orbitals for SP , SP and SP carbon3 2
atoms.. Then these hybrid orbital are used as the basis set for creating molecular
orbitals in polyatomic molecules. The energies of the orbitals are estimated and their
shapes approximated using a graphical method.
1Tutorial #27 Molecular Orbitals
Contents
1 Atomic Orbitals . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1 Hydrogen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 Carbon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2 Simple Molecular Orbitals . . . . . . . . . . . . . . . . . . . . . . 5
2.1 Rules for Orbital Combinations . . . . . . . . . . . . . . . . . . . 5
2.2 The Hydrogen Molecule . . . . . . . . . . . . . . . . . . . . . . . 6
2.2.1 Interaction Energy . . . . . . . . . . . . . . . . . . . . . . 6
2.2.2 Shape of the Bonding Molecular Orbital . . . . . . . . . . 6
2.2.3 Shape of the Antibonding Molecular Orbital . . . . . . . 7
2.3 Relative Energies of Orbitals . . . . . . . . . . . . . . . . . . . . 8
2.4 Adding Circles – Graphical Orbital Combinations . . . . . . . . . 9
2.4.1 Graphical Molecular Orbitals in H . . . . . . . . . . . . . ...