Probing electronic rearrangement during chemical reactions

During a chemical reaction the electronic structure of the reactants reforms to the structure of the products. In the simplest case, an old bond is broken and simultaneously a new bond is formed. Even when this change occurs adiabatically, meaning that the electronic charge distribution tracks the motion of the nuclei without change in its quantum state, there is a displacement of charge, particularly so if there is a switch from a covalent to an ionic bonding. This reorganization can be probed by light emitted during the very collision. The F + H₂ reaction is used as a computational example.