Punched Card Calculation of Resonance Energies

The calculation of resonance energies can be greatly simplified by using punched card machines. Two methods are developed. The first is easy to apply and works well for 8‐, 10‐, and 12‐electron problems. This is used for naphthalene. The results lend themselves well to a bond probability calculation from which bond distances in good agreement with other methods are obtained. The second procedure is longer, but makes possible the calculation of anthracene and phenanthrene resonance energies. These are −2.951α and −3.019α, respectively. Bond probabilities and lengths were also calculated from these data.

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