For each conformer, we also computed six polarized QM ESPs by imposing uniform external fields of magnitude 0.01 a.u. in the +x, -x, +y, -y, +z, -z directions, and computed their differences relative to the baseline QM ESPs, V diff,ikl , where l ∈ [1, . . . , 6] indexes the field directions. Using different field directions allows for averaging over any anisotropy in the induced polarization. The field strength of 0.01 a.u. was chosen to approximate the external electric field generated by a sodium ion about 4Å away. We used global optimization with the Nelder-Mead method in SciPy 51 to find typed polarizabilities that minimize the following error function,