Electron-capture collisions ofH+with ground- and excited-state Na

Pseudopotential molecular-structure calculations have been used to obtain the low-lying interaction energies for Na${\mathrm{H}}^{+}$. The wave functions were used to calculate accurate radial and rotational coupling matrix elements. Scattering calculations which include electron translational factors were performed using up to eight coupled channels for laboratory energies 0.1 to 10 keV. Electron capture from ground-state $\mathrm{Na}3s$ yields cross sections in the ${10}^{-15\mathrm{}}$-${\mathrm{cm}}^2$ range of which the dominant products are $\mathrm{H}2s$ and $\mathrm{H}2p$. Electron capture from excited $\mathrm{Na}3p$ does not show an enhanced cross section relative to capture from the ground state even though the energy gap $\Delta E(R=\infty )$ to the dominant electron-capture channel is reduced from 1.74 to 0.36 eV.