Inelastic processes leading to excited-state formation inHe+andH+collisions with Na and K

Energy partitioning among accessible product excited states has been spectroscopically studied in a beam apparatus for ${\mathrm{He}}^{+}$ and ${\mathrm{H}}^{+}$ collisions with Na and K atoms in the kinetic energy range 10-800 eV. The dominant observable inelastic channel in all collision systems was found to be collision-induced excitation yielding resonance radiation. While excited states of ${\mathrm{K}}^{+}$ formed by charge exchange were also observed, no analogous ${\mathrm{Na}}^{+}$ emissions were detected; the absence of ${\mathrm{Na}}^{+}$ emissions is attributed to inefficient energy conversion. Comparison of data from one-electron and two-electron processes supports the propensity rule which states that the former are generally favored.