Where N i is the number of electrons associated with atom i and z i is the nuclear charge. The electron density is calculated as the direct solution of the inhomogeneous Poisson equation in a medium with a dielectric constant = 4. It was found that "half-polarizing" the molecule with a low dielectric constant resulted in non-bonded terms that are suitable for condensed phase modelling. Including polarization in this manner allows us to avoid parametrizing any BCC or charge scaling factors as employed by CGENFF, OPLS/CM1A and OPLS/CM5. Additionally, the QUBE FF employs the TS method to derive the A ij and B ij terms of the FF in equation 1 by rescaling reference free atom data, proportionally to AIM electron densities. The dispersion coefficient B i is estimated as: