To obtain an initial set of frozen populations, L DRESP is minimized w.r.t. the site populations n 0 as well as it's Slater exponents ζ. This is performed for each of the 4 nucleobases in isolation of the others such that no effects of interactions between fragments are taken into account during the initial ESP fitting procedure. Because we are using density functions that can account for a reasonable amount of electron penetration, two additional vdW radii intervals were added to the original RESP procedure. The resulting Connolly surfaces were computed at multiples of the vdW Bondi radii from 1.0 -2.0 at intervals of 0.2. Hyperbolic scaling factors of a = and b = were also used in the minimization. Additionally, the python based code used to perform the DRESP fitting has been made available to the public via it's GitHub repository. Interested readers can find further details of the algorithm in the ESP point generation on Connolly surfaces.