Fig. 3

Collision-energy dependent charge-transfer (CT) rate coefficients. Reaction rate coefficients as a function of collision energy and state of Rb for a \({{\rm{N}}}_{2}^{+}\) + Rb and b \({{\rm{O}}}_{2}^{+}\) + Rb. Blue [orange] symbols indicate CT rate coefficients for collisions with Rb in its \({}^{2}{S}_{1/2}\) [\({}^{2}{P}_{3/2}\)] state. The theoretical Langevin rate coefficients for collisions in these channels are the blue [orange] solid lines. Dash-dotted lines represent fits to the experimental data, except for the orange dash-dotted line in b which represents the prediction of the rate coefficient for dominant ion-quadrupole capture. The red and green diamonds in a represent CT rate coefficients for N\({}_{2}^{+}\, +\) Rb (\({}^{2}{S}_{1/2}\)) computed by quasiclassical trajectory simulations and quantum scattering calculations, respectively. Error bars represent one standard error.