OPTIMIZATION OF PARAMETERS OF NONBONDED INTERACTIONS IN A SPECTROSCOPICALLY DETERMINED FORCE-FIELD

A procedure is given by which parameters of nonbonded interactions in a molecular mechanics energy function can be optimized for maximum com patibility with ab initio force fields and structures. The method is b ased on a previously derived transformation of ab initio valence param eters to the molecular mechanics formalism. Explicit analytical expres sions for the derivatives of the molecular mechanics force constants a nd reference geometry parameters with respect to the parameters of the nonbonded interactions are derived. The form of the goodness-of-fit f unction is discussed. A first application to a set of alanine dipeptid es is described.