Example 7.1. Comparison of Attractive Forces

We notice that the potential energy for all physical attractive forces is of the type  

B is a positive constant for each type of forces except for the dipole-dipole ones, where it is also a function of the reciprocal temperature. It represents, thus, a measure of the potential energy at a given distance. 

With this backgroimd, calculate B values for the different types of forces exerted in the following three pairs of molecules at 273 K  

1 through 7.5.6 are approximations and are useful for comparison purposes only. 

In certain molecules, such as CO2 for example, charge concentrations in four locations within the molecule give rise to quadrupoles and additional intermolecular forces. They are smaller, but not insignificant. 

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