Ion migration following charge transfer reactions in rare-gas solids: The role of hole hopping

Recent experiments have shown that photoinduced charge transfer processes in rare-gas solids, such as Xe+Cl₂+2hv→Xe⁺Cl^-+Cl result in highly efficient separation of the halogen atoms, even at very low temperatures (T≤20 K). In this study a mechanism for this is proposed in which hopping of the hole charge among the Xe atoms induces migration of the Cl^- by a Coulomb pulling effect. Simulations combining a stochastic description of hole hopping with classical trajectory (molecular dynamics) calculations of atomic motions yield results in good qualitative accord with the experimental findings. Simulations ignoring hole migration but otherwise employing realistic potentials fail to reproduce the separation of halogen atoms.