Interpretation of glory undulations in scattering cross sections: amplitudes

The interpretation of the amplitude ΔQ of the glory undulations is given in terms of the coefficients Ri of a semiclassical expansion of the form ΔQ = v1/2 (R0 + R1 E−1 +···) where v is the relative velocity and the E the relative kinetic energy. The Ri give a measure of the force in the vicinity of the distance of closest approach. These coefficients can be used with the analogous coefficients for the spacing of the undulations to provide combinations that depend only on the shape of the potential and not on its scale. Examples are given for square-well and Lennard-Jones (n, 6) potentials.