Bond type [#7:1]-[#7:2], N=32 The fitting process moved most bond lengths and angles closer to the diagonals of these scatter plots, implying better agreement between MM and QM, as expected based on Figure . For a clear example, see Figure (left), where a change in the equilibrium bond length shifted the MM results to the diagonal and thus into better agreement with QM. However, a few of these scatter plots are more problematic. For example, Figure (right), which examines a general N=N bond stretch, shows a small shift of the data points toward the diagonal, but does not correct the fact that this bond length falls in a narrow range across all the MM geometries but is varied in the QM geometries. In cases like this, greater accuracy might be achieved by creating two or more force field types for N=N bonds, rather than just one. Before taking such a step, though, one should consider whether the variations in the QM bond lengths trace to varied amounts of strain placed on the bond by other components of the structure. If so, then the accuracy of the N=N bond lengths should be improved by adjustment of other parameters that would correct the strain, rather than correcting parameters intrinsic to the bond itself.