New recombination mechanism: Tidal termolecular ionic recombination

The measured rate coefficient α for ${\mathrm{Xe}}_2^{+}$+${\mathrm{Cl}}^{\mathrm{-}}$→${\mathrm{XeCl}}^{\mathrm{*}}$+2Xe (and similar processes) is far higher than had been expected. The exciting experimental results are reminiscent of assisted mutual neutralization, but this cannot occur. Monte Carlo simulation that allows for the ${\mathrm{Cl}}^{\mathrm{-}}$-${\mathrm{Xe}}^{+}$, ${\mathrm{Cl}}^{\mathrm{-}}$-Xe, and ${\mathrm{Xe}}^{+}$-Xe forces shows that the rotational and vibrational modes of ${\mathrm{Xe}}_2^{+}$ tend to be excited by the passage of ${\mathrm{Cl}}^{\mathrm{-}}$ through perihelion. Because of this electrostatic tidal action the orbit contracts and the internal energy of ${\mathrm{Xe}}_2^{+}$ increases, leading to dissociation. The measured values of α are reproduced satisfactorily.