FIGURE 4.

(a) Molecular schematic representation of the pseudobond approach for polarizable QM/MM optimization, with QM (MM) atoms in the green(blue) shaded regions, and boundary atoms shaded in purple. In this approach, a polarizable QM/MM involves four calculations: (b) QM polarized by the static MM field (blue shaded region), (c) MM without charges on QM (green circle) or boundary atoms (purple shaded atoms), (d) MM polarization including static (approximate) QM field (green and purple shaded regions), (e) MM optimization with static field from QM and boundary atoms (green and purple shaded regions)⁶⁶