Cross Sections for Charge-Exchange Reactions of the TypeH++H(n1l1m1)→H(n2l2m2)+H+

We consider charge-exchange reactions of the general type ${\mathrm{H}}^{+}+\mathrm{H}\left(n_1{l}_1{m}_1\right)\to \mathrm{H}\left(n_2{l}_2{m}_2\right)+{\mathrm{H}}^{+}$, and use some recently derived sum rules to get comparatively simple closed expressions for the cross section. Calculations are performed in the Born approximation. We consider all excited target H atoms with $n_1\ge 2$ and all (appropriate) $l_1\le 3$; we average over $m_1$. We evaluate the total cross section for formation of final states with given principal quantum number $n_2$; i.e., we sum over $l_2$ and $m_2$. These results may be easily modified to include the case where the target atoms are H-like alkali atoms.