Electron capture into excited states of hydrogen

A simple extension is made to a recent modified binary-encounter approach to calculate the cross sections of electron capture into excited states of hydrogen for protons incident on atomic hydrogen and helium. The present cross sections of electron capture into the nth principal shell of hydrogen compare satisfactorily with experimental results and appear to exhibit an n-3 dependence at high impact energy. The shortcomings of previous classical methods are also discussed. A method is suggested for distinguishing electron capture into the excited substates H(nl). (author)