The distortion effects are investigated for the ($\alpha ,2\mathrm{}\alpha$) reaction in the framework of the distorted-wave impulse approximation at intermediate energies (> 100 MeV) for various nuclei. It has been found that the main effect of the distortion is to reduce the cross section. This reduction factor decreases with the energy and, at a particular energy, increases with the mass number. The distortion is also found to change the shape of the "distorted" momentum distribution around the secondary maxima. Comparison of the calculated results with the available data at 850 MeV on ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ gives the spectroscopic factor in excellent agreement with the theoretically estimated value.

[NUCLEAR REACTIONS Intermediate energies, ($\alpha ,2\mathrm{}\alpha$), DWIA.]

• Received 1 August 1983

DOI:https://doi.org/10.1103/PhysRevC.29.1105