Propensity rules for magnetic-substate distributions for electron capture from excited states of atoms by multiply charged ions

The propensity rules for populating magnetic substates in electron-capture processes from excited target atoms are examined theoretically using the close-coupling expansion method with two-center atomic orbitals. It is shown that if the quantization axis is chosen to be perpendicular to the scattering plane, the dominant magnetic substate populated for each final nl state is m=-l, irrespective of the magnetic quantum number of the initial state. Electron-capture processes from 2s and oriented 2p states of hydrogen atoms in collisions with ${\mathrm{He}}^{2+}$ and ${\mathrm{Li}}^{3+}$ are examined.