Mutual neutralization in low-energy collisions of Na+ + H- ions

The low-energy mutual neutralization (MN) reactions Na+ + H- → Na(nl) + H have been studied by employing the full quantum-mechanical molecular-orbital close-coupling (QMOCC) method over a wide energy range of 10-3 to 103 eV/u. Total and state-selective cross sections have been investigated and compared with the available theoretical and experimental data, and the state-selective rate coefficients for the temperature range of 100-10000 K have been obtained. In the present work, all the necessary highly excited state are included, and the influence of rotational couplings and 10 active electrons are considered. It is found that in the energy below 10 eV/u, the Na(4s) state is the most dominant exit state with a contribution of approximately 78% to the branch fraction, which is in best agreement with the experimental data. For energies above 10 eV/u, the MN total cross section is larger than those obtained in other theoretical calculations and shows a slow decreasing trend because the main exit states change, when the energy is above 100 eV/u, the dominant exit state becomes the Na(3p) state, while the Na(4s) state becomes the third most important exit state.