The Mechanism of Chromatographic Retention - Chromatographic Interactions > Dispersive Interactions > Page 5

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