Intermolecular forces Relatively weak interactions that occur between molecules

Intermolecular forces relatively weak interactions that occur between molecules. (16.1)... 

Intermediate a species that is neither a reactant nor a product but that is formed and consumed in the reaction sequence. (12.6) Intermolecular forces relatively weak interactions that occur between molecules. (10.1)... 

In order to learn how to achieve the selectivity required to resolve a pair of enantiomorphs, the mechanism of retention must be fully understood. This means that the molecular forces that control retention must be defined, their mode of action identified, and their effect on the distribution coefficient (K) examined. The magnitude of (K) depends on the relative affinity of the solute for the two phases. Consequently, the stationary phase must be chosen to interact strongly with the solutes to achieve a separation i.e. the intermolecular forces between solute and stationary phase must be relatively large). In contrast, the interactions between the solute molecules and the mobile phase should be chosen to be relatively weak, to allow the stronger forces to dominate in the stationary phase and produce the required retention and selectivity. This will naturally occur in GC, as the probability of interaction (collision between solute and gas molecules) is very small compared with that in a liquid, and due to the small mass of the mobile phase molecules, the strength of any interactions that do occur will be extremely weak. This will not be true in LC, and the mobile phase must be chosen so that the type of interactions that take place with the solute will be weaker than those that take place between the solute and the stationary phase. This will become clearer when the different types of molecular interactions are understood. 

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