The Quantum Mechanics of Unsaturated and Aromatic Molecules: A Comparison of Two Methods of Treatment

A comparison is made of two quantum‐mechanical methods of treatment of unsaturated and aromatic organic molecules. The HLSP treatment, which is based upon the use of Slater valence‐bond eigenfunctions, seems to give results in somewhat better general agreement with experiment than the HMH, which is based upon the use of molecular orbitals of the Hund‐Mulliken type. The latter, however, can be extended to a wider variety of problems. The problems considered include the energy relations among hydrocarbons, the dissociation of aryl substituted ethanes, the electron‐affinity of free radicals and the acid strength of hydrocarbons.