Our analysis of the electric field response of the reaction starts with a lone reactant ethylene molecule (Scheme 3) and three 0.0125au applied external electric fields (EEFs) oriented orthogonally along the C=C bond axis (y, pointing from C2 to C1), in the molecular plane (x), and out of the molecular plane (z). Table 2 lists regional condensed electron counts for ethylene with no electric field (NEF) and for each of the oriented applied fields, along with their difference (𝜌 667 -𝜌 867 ) and percent difference (𝜌 667 -𝜌 867 )/𝜌 867 × 100. Starting with the atomic basins, overall there is an inter-atomic charge transfer of around a twentieth of an electron for the symmetry breaking 𝑥 and 𝑦 fields, and negligible transfer for the symmetry conserving 𝑧 field. The direction of 𝑥 and 𝑦 charge transfer is as expected for a homogeneous electron gas; opposite that of the field.