Classical cross sections for the electron ionization of the degenerate levels of the excited states of atomic hydrogen

The classical theory of Gryzinski is used to obtain cross sections for the electron ionization of the degenerate levels of atomic hydrogen. The results are compared with the Born approximation cross sections and it is found that the agreement is good. As the principal quantum number is increased the classical and quantal cross sections tend to one another at all values of the incident electron energy for all azimuthal quantum numbers.