Molecular Mechanics

Abstract

Molecular mechanics (MM) rests on a view of molecules as balls held together by springs. The potential energy of a molecule can be written as the sum of terms involving bond stretching, angle bending, dihedral angles and nonbonded interactions. Giving these terms explicit mathematical forms constitutes devising a forcefield, and giving actual numbers to the constants in the forcefield constitutes parameterizing the field. An example is given of the devising and parameterization of an MM forcefield. Calculations on biomolecules is a very important application of MM, and the pharmaceutical industry designs new drugs with the aid of MM. Organic synthesis now makes considerable use of MM, which enables chemists to estimate which products are likely to be favored and to devise more realistic routes to a target molecule. In molecular dynamics MM is used to generate the forces acting on molecules and hence to calculate their motions.