Inelastic S-wave positron--hydrogen scattering

The variational methods of Kohn and Hulth\'en are used to calculate the scattering parameters of the positron-hydrogen rearrangement collision. The $R$-matrix elements are computed for positron energies 0-0.33 a. u. with accuracy of (1-10)%. It is also shown that a good approximation to the diagonal elements of the $R$ matrix can be obtained by ignoring the coupling between the channels.