Parameters for potential functions

Until recently, the choice of parameters for potential functions was based mostly on empirical information. Significant developments in both computer hardware and quantum chemical calculation software during the past decade have made possible derivation of the force field parameters from first-principles calculations. 

What is intended in the present contribution is to review a recently developed theory of the dynamics of molecular liquids which overcomes all these unwelcome features of currently available theories a self-contained theory that requires only the knowledge of parameters for potential functions and molecular geometry (such as bond lengths) as in simulation studies a theory whose memory function incorporates the non-Markovian effects a theory which accounts for all the characteristic features of collective excitations in molecular liquids. This will be accomplished by generalizing successful frameworks described so far in this section to molecular liquids based on the interaction-site representation. 

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