Inelastic Alpha Scattering and Associated Gamma Radiation. III

In a 0-2-0 transition in a deformed nucleus excited by inelastic scattering of $\alpha$ particles, the pattern of $\gamma$ radiation sometimes rotates rapidly backward as the $\alpha$-particle scattering angle is increased. Previous papers employing a two-dimensional model have shown that this striking behavior may be attributed to the "beats" between incoming and outgoing waves at the edges of the nucleus. The most conspicuous effect there neglected was that of the "focus" of intensity of each of the distorted waves in the middle of its "shadow side" of the nucleus. Here it is shown that the influence of this effect modifies but need not destroy the reverse-rotation phenomenon, and that it provides an explanation for the failure of the reverse rotation to persist for small-angle scattering in most of the observations.