The key finding here is that picturing the response of simple negative charges to an electric field appears to provide some intuition regarding the van der Waals regions, but the induced response of the inner valance molecular charge redistribution does not follow such a simplistic model. This interdependent behavior was not evident in the inter-atomic charge transfer, and only via the combined approach of atomic and bond regional property analysis have we arrived at a clear picture of ethylene's response to electric fields. Table . Atomic basin and bond bundle regional valence charge densities in the cis-butadiene + ethylene transition state with and without 0.0125au electric fields oriented along the ±z directions. Symmetrydegenerate atoms have been combined as indicated parenthetically values for the TS structure with/without the ±𝑧 fields. The total valence density of an atom is calculated as its total density minus its number of core electrons, 𝜌 < = 𝜌 -𝜌 =2>, . The gradient bundle condensed valence density is then calculated, like the condensed deformation energy of Figure , by subtracting the spherical atomic reference amount of core density from each gradient bundle, 𝒫 < = 𝒫 -𝒫 =2>,,./0 . Note that symmetry degenerate atomic basins have been averaged.