Hyperspherical close-coupling calculation of positronium formation and excitation cross sections in positron-hydrogen scattering at energies below the H(n=4) threshold

A hyperspherical close-coupling method is used to calculate the elastic, positronium formation and excitation cross sections for positron collisions with atomic hydrogen at energies below the H(n=4) threshold for L=0 and 1 partial waves. A new two-dimensional coordinate transformation is used such that the Schrodinger equation at large hyper-radii can be solved accurately. The coupled hyper-radial equations are integrated to a large hyper-radius at which the solution is matched to the dipole states in the outer region. From the extracted K-matrix, the elastic, positronium formation and atomic hydrogen excitation cross sections are computed. Resonance positions, total widths, and partial cross sections are also examined and compared with those from other calculations.