and, 
| where (r) | is the density of the medium, |
| (M) | is the molecular weight, |
| (NA) | is Avogadro's Number |
| and (PM) | is the molar polarizability, noting that the number of molecules per unit volume is Nr/M. |
The molar
polarizability is an inverse function of 
, the molar volume. A schematic of dispersive
interactions is shown in figure 1.
Figure 1. Schematic Representation of Dispersive Interaction
