Article révisé par les pairs
Résumé : Valuable theoretical predictions of nuclear dipole excitations in the whole nuclear chart are of great interest fordifferent applications, including in particular nuclear astrophysics. Here we extend our large-scale calculations ofthe E1 andM1 absorption γ -ray strength function obtained in the framework of the axially symmetric deformedquasiparticle random-phase approximation (QRPA) based on the finite-rangeD1MGogny force to the deexcitationstrength function. To do so, shell-model calculations of the deexcitation dipole strength function are performedand their limit at low γ energies used to complement phenomenologically the QRPA calculations. We compareour final prediction of the E1 and M1 strength with available experimental data at low energies and show that afairly good agreement is obtained. Predictions of the dipole strength function for spherical and deformed nucleiwithin the valley of β stability as well as in the neutron-rich region are discussed and compared with traditionalLorentzian-type prescriptions. Its impact on the total radiative width as well as radiative neutron and protoncapture cross sections is studied.