Politzer's ratio

This plot of computational results for the Kimball model of normal, staggered hydrocarbons C1…C26 has been shown.

P. Politzer (1976) J Chem Phys 64:4239 has used the ratio -(Vne+2*Vnn)/(Vee-Vnn) which varies very slightly for a large range of molecules. It has been widely tested by Snyder & Basch (1972), "Molecular wave functions and properties", Wiley, New York, who found a value of 6.70 ± 0.44. Dr. E. Honegger (1987) has discussed this relation carefully and added 40 test molecules.
The plot, above, shows the exact Politzer number for the Kimball hydrocarbons tested.
The molecules shown in the gallery (page above) and a couple more have been tested similarly. The following table depicts the Politzer ratios determined:

The average value of the set of 53 molecules is 6.61 ± 0.54, using the energy components derived by Kimballs model from experimental structures of variable precision.