Accuracy of calculating the exchange part of the real alpha-nucleus potential

Abstract

In the present work, we test the validity of replacing the nondiagonal matrix \ensuremath{\rho}(r\ensuremath{\rightarrow},r\ensuremath{\rightarrow}\ensuremath{'}) appearing in the exchange part of the \ensuremath{\alpha}-nucleus optical potential by an approximation based on the density matrix expansion (DME) used frequently in nuclear structure calculations. We have found that for the recently derived BDM3Y nucleon-nucleon force the DME may produce a maximum error more than 29% in the \ensuremath{\alpha}-nucleus potential. \textcopyright{} 1996 The American Physical Society.