Figure 6.

Accuracy of centroid-collocation and qualocation methods for problems with charges in both the high- and low-dielectric regions. The problem geometry is the same as used in Figure 2, with an additional −1e charge placed in the low-dielectric region at (0, 0, 6 Å). The qualocation results, denoted by solid lines with circles of varying sizes, are nearly indistinguishable except in the immediate vicinity of the charge in the high-dielectric region.