Partial Charge-Transfer Reactions at Thermal Energies

Thermal energy reaction rate constants are reported for the partial charge‐transfer reactions ${\mathrm{Ca}}^{\text{2+}}+\mathrm{NO}\to {\mathrm{Ca}}^{+}+{\mathrm{NO}}^{+}$ and ${\mathrm{Mg}}^{\text{2+}}\mathrm{+\; X\; \to }{\mathrm{Mg}}^{+}{\mathrm{+\; X}}^{+}$ with X as Xe, NO, O₂, N₂O, CO₂, CO, SO₂, NH₃, and NO₂. The rate constants for single electron transfer of polyatomic neutrals are often three orders of magnitude larger than the rate of electron transfer from Xe. Within a curve crossing model the molecular data yield approximate efficiencies of electron transfer from 2.5 to 14.4 Å. The difficulties of using a curve crossing model for polyatomic molecules and a simple Landau—Zener calculation at thermal energies are briefly discussed.