Energy Dependence of Elasticα-Particle Scattering: Microscopic Model

The energy dependence of elastic $\alpha$ scattering from ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ between 39.6 and 115.4 MeV is determined using a microscopic optical model. The agreement between theory and experiment improves as the energy increases. We find that both the real and imaginary parts of the optical potential are well described by a strength depending linearly on energy. For the real part the slope is about half the corresponding value for proton scattering; no theoretical estimates of this quantity are presently available.