FIGURE 17.

Energy changes of the various potential terms. Nonbonded interactions should be calculated only between particles that are not bonded (Elber et al., 1995). In empirical molecular mechanics, particles that are separated by more than three bonds are considered unbound and the nonbonded interactions are computed for them in full (electrostatic and Van der Waals energy terms). Particles that are separated by three bonds are considered an intermediate case, in which their interactions are scaled down to reproduce known torsion barriers (electrostatic and Van der Waals energy terms of the 1–4 pairs). The change in electrostatic energy is the largest during B-Z transition.